Category: Science


Protein Requirements for Athletes

A well-designed diet for an athlete is a combination of proper energy intake, proper timing, along with proper training. An energy deficient diet during training may lead to loss of muscle mass and strength, increased susceptibility to illness, and increased prevalence of overreaching and/or overtraining (7). People who follow a general fitness program can generally meet their nutritional needs with a healthy, well-balanced diet. However, the caloric and protein needs of a highly trained athlete are different
and will be discussed here.

Considerable debate ensues regarding the proper intake of protein for athletes. The current recommended level of protein intake (0.8 g/kg/day) is estimated to be sufficient to meet the needs of nearly all (97.5%) healthy men and women age 19 years and older (2). This amount of protein intake may be appropriate for non-exercising individuals, but it is “likely not suffi cient to off set the oxidation of protein/amino acids during exercise (approximately 1 –5% of the total energy cost of exercise)” (2). If an athlete does not ingest sufficient amounts of protein, he or she will maintain a negative nitrogen balance, which can increase protein catabolism and slow recovery (7). Nitrogen balance is quantifed by calculating the total amount of dietary protein that enters the body and the total amount of the nitrogen that is excreted (9). Table 1 provides general guidelines for protein and caloric intake based on the level of activity.

It is important to remember that not all protein is the same. Proteins differ based on the source, the amino acid profile and the methods of isolating the protein (7). Great dietary sources of low-fat, high-quality protein are skinless chicken, fish, egg whites and skim milk while the highest quality supplemental sources are whey, colostrum, casein, milk proteins and egg protein (7). The Food
and Agriculture Organization (FAO) established a method for determining the quality of a protein source by “utilizing the amino acid composition of a test protein relative to a reference amino acid pattern and then correcting for differences in protein digestibility,” (4).

Two of the most widely used protein supplements are casein and whey, which can both be found in milk products. Research has demonstrated that “whey protein elicits a sharp, rapid increase of plasma amino acids following ingestion, while the consumption of casein induces a moderate, prolonged increase in plasma amino acids that was sustained over a 7-hour postprandial time period,” (1). The International Society of Sports Nutrition (ISSN) recommends that athletes obtain protein through whole foods, and when supplements are ingested they should contain both casein and whey “due to their ability to increase muscle protein accretion,” (2).

While casein and whey have been found to be beneficial, other research exists to support the benefits of leucine. Approximately one third of skeletal muscle protein is made up of the branched-chain amino acids (BCAA), leucine, isoleucine and valine (8). Research suggests that of these three, leucine plays the most significant role in stimulating protein synthesis (5). Therefore, supplementation
of branched-chain amino acids may be beneficial to athletes.

Researchers at the Department of Human Biology at Maastricht University in the Netherlands, conducted a study to determine post-exercise muscle protein synthesis and whole body protein balance following the combined ingestion of carbohydrates with or without protein and/or free leucine (6). Eight male subjects were randomly assigned to three trials in which they consumed drinks containing carbohydrates, carbohydrates/protein, or carbohydrates/protein/leucine following 45mins of resistance exercise. Results of the study showed that whole body protein breakdown rates were lower, and whole body protein synthesis rates were higher in the carbohydrate/protein and carbohydrates/protein/leucine trials compared with the carbohydrate trial. The addition of leucine resulted in a lower protein oxidation rate compared with the carbohydrate/protein trial. The study concluded that
co-ingestion of protein and leucine stimulates muscle protein synthesis and optimizes whole body protein balance compared
with the intake of carbohydrates only (6).

BCAA supplementation has been shown to be particularly beneficial during aerobic exercise because of an increase in the free tryptophan/BCAA ratio (5). During prolonged aerobic exercise, the amount of free tryptophan increases and therefore the amount of tryptophan entering the brain increases, resulting in fatigue (5). BCAAs are transported to the brain through the same carrier as tryptophan, so when BCAAs are present in the plasma, in signifi cant amounts, they may decrease the amount of tryptophan reaching the brain, therefore decreasing feelings of fatigue (2). It has been suggested that the recommended daily allowance (RDA) for leucine alone should be 45 mg/kg/day for sedentary individuals, and even higher for active individuals (8). A deficiency in BCAA intake from whole foods can be supplemented by consuming whey protein (2).

In conclusion, major organizations recommend athletes consume more than the RDA for protein, approximately 1.4 – 2.0 g/kg of body weight/d (2,4). Every attempt to obtain protein from whole foods is ideal; however supplementation is a safe way of obtaining the needed amounts of protein when necessary.

Table 1. Caloric and Protein Intake Guidelines

Activity Level Caloric Intake Protein Intake
General Activity 25 -35 kcals/kg/day 0.8 – 1.0 g/kg/day
Strength Training Athletes 50 – 80 kcals/kg/day 1.4 – 1.8+ g/kg/day
Endurance Athletes 150 – 200 kcals/kg/day 1.2 – 1.4 g/kg/day

Source: The Position Statement from the Dietitians of Canada, the American Dietetic Association, and the American College of Sports Medicine, Canadian
Journal of Dietetic Practice and Research in the Winter of 2000, 61(4):176-192 (3).

References

1. Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, and Beaufrere, B. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proceedings of the National Academy of Sciences of the United States of America 94(26): 14930 – 5, 1997.

2. Campbell, B, Kredier, R, Ziegenfuss, T. et al. International Society of Sports Nutrition position stand: Protein and exercise. Journal of the International Society of Sports Nutrition 4(8), 2007.
3. The Position Statement from the Dietitians of Canada, the American Dietetic Association, and the American College of Sports Medicine. Canadian Journal of Dietetic Practice and Research 61(4): 176 – 192, 2000.
4. Darragh, A, and Hodgkinson, S. Quantifying the digestibility of dietary protein. The Journal of Nutrition 130: 1850S – 1856S, 2000.

5. Kimball, SR, and Jefferson, LS. Signaling pathways and molecular mechanisms through which branched-chain amino acids mediate
translational control of protein synthesis. Journal of Nutrition 136(1 Suppl): 227S – 31S, 2006.

6. Koopman R, Wagenmakers AJ, et al. Combined ingestion of protein and free leucine with carbohydrate increases post-exercise muscle protein synthesis in vivo in male subjects. American Journal of Physiology Endocrinology and Metabolism 288(4): E645 – 53, 2005.

7. Kreider, RB, Wilborn, CD, Taylor, L, Cambpell, B, et al. ISSN exercise & sport nutrition review: Research & recommendations. Journal of the International Society of Sports Nutrition 7(7.2), 2010.

8. Leucine supplementation and intensive training. Sports Medicine. 27(6): 347 – 58, 1999.

9. Rand WM, Pellett, PL, and Young, VR. Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults. American Journal of Clinical Nutrition 77(1): 109 – 27, 2003.

 

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GRIP WIDTH AND FOREARM ORIENTATION EFFECTS ON MUSCLE ACTIVITY DURING THE LAT PULL-DOWN

 

STEPHEN J. LUSK, BRUCE D. HALE, AND DANIEL M. RUSSELL

Department of Kinesiology, The Pennsylvania State University—Berks, Reading, Pennsylvania

 

ABSTRACT

 

Lusk, SJ, Hale, BD, and Russell, DM. Grip width and forearm orientation effects on muscle activity during the lat pull-down. J Strength Cond Res 24(7): 1895–1900, 2010—Based on electromyographic (EMG) studies, an anterior (in front of the face) wide grip with a pronated forearm has been recommended as the optimal lat pull-down (LPD) variation for strengthening the latissimus dorsi (LD) (Signorile, JF, Zink, A, and Szwed, S. J Strength Cond Res 16: 539–546, 2002; Wills, R, Signorile, J, Perry, A, Tremblay, L, and Kwiatkowski, K. Med Sci Sports Exerc 26: S20, 1994). However, it is not clear whether this finding was because of grip width or forearm orientation. This study aimed to resolve this issue by comparing wide-pronated, wide-supinated, narrow-pronated, and narrow-supinated grips of an anterior LPD. Twelve healthy men performed the 4 grip variations using an experimentally determined load of 70% of 1 repetition maximum. Two trials of 5 repetitions were analyzed for each grip type. Participants maintained a cadence of 2-second concentric and 2-second eccentric phases. The grip widths were normalized for each individual by using a wide grip that corresponded to their carrying width and a narrow grip that matched their biacromial diameter. Surface EMG of the LD, middle trapezius (MT), and biceps brachii (BB) was recorded, and the root mean square of the EMG was normalized, using a maximum isometric voluntary contraction. Repeated-measures analysis of variance for each muscle revealed that a pronated grip elicited greater LD activity than a supinated grip (p , 0.05), but had no influence of grip type on the MT and BB muscles. Based on these findings, an anterior LPD with pronated grip is recommended for maximally activating the LD, irrespective of the grip width (carrying width or biacromial diameter).

 

KEY WORDS EMG, latissimus dorsi, pronation, supination

 

INTRODUCTION

During a lat pull-down (LPD), the humerus is adducted under load via a pulley system. This exercise is commonly employed in an effort to strengthen the latissimus dorsi (LD) muscle, hence its name, and is also expected to activate the rhomboids, middle trapezius (MT), and biceps brachii (BB) muscles. There are several different variations of body position, grip width, and forearm orientation that can be employed. The bar can be pulled down in front of the face (anterior LPD) or behind the head (posterior LPD), the hands can be narrowly or widely spaced, and the radioulnar joint

can be pronated or supinated. Yet research to determine the optimal variation of the LPD for particular muscle development is limited. Currently, much of the literature on the strength-building capacity of this exercise is based on

personal beliefs and experiences (3,4,16), although a few investigations have used electromyography (EMG) to quantify the amount of activity in different muscles during different types of LPDs (10,12,14,15). These studies have provided several scientifically based weight training recommendations, but questions remain about the most effective combination of grip width and forearm orientation. Research has led to the general consensus that the anterior LPD is preferred to the posterior LPD. Most studies comparing the activity of the LD under both conditions have found that the anterior LPD elicits greater muscle activation (by EMG) than the posterior LPD (11,12,14). Only 1 study failed to observe any significant difference in muscle activity between anterior and posterior LPDs (15). There have also been safety concerns that pulling down the bar behind the head puts the arm into horizontal abduction with excessive external rotation, placing unnecessary stress on the anterior shoulder (4,9,16). Functionally, it would also appear that the anterior LPD more closely mimics activities of daily living than the posterior LPD. Because of these past results and safety concerns, the current research investigation focused only on variations of the anterior LPD. A wide grip front pull (anterior) has been proposed as the most effective LPD variation for the developing the LD (12). This claimis based solely on 2 EMGstudies comparing a wide grip-pronated forearm position (wide-pronated [WP]) with a narrow grip–supinated forearm position (narrow supinated [NS]), which have found significantly greater LD activation with WP than NS (12,15). However, 1 EMG study failed to observe any significant difference in LD activity between WP and NS conditions (10). These contradictory results may be explained by 2 major differences in experimental design. Firstly, EMG was recorded during an isometric contraction (10) in contrast to EMG of concentric and eccentric phases of the LPD (12,15). Recording EMG during isotonic muscle actions provides a better assessment of the amount of muscle activity during a typical LPD exercise. Secondly, participants selected their own workload (10), with most performing at about 30–40% of 1 repetition maximum (1RM), whereas the workload was experimentally controlled in the other 2 studies at 10RM (12) and 70% of maximum voluntary contraction (MVC) (15). It is more valid to assess muscle activity at a level close to typical training workloads (e.g., 70% of 1RM as per American College of Sports Medicine (ACSM) guidelines [1] for strength training), rather than 30–40% of 1RM. These criticisms suggest that the observation of greater LD activity for the WP than the NS grip (12,15) is a more valid and reliable finding for providing isotonic exercise recommendations. However, the recommendation that a wide grip is preferred over a narrow grip (12,13) cannot be directly drawn from the finding of an advantage of WP over NS. In addition to varying the grip width between conditions (7), the forearm orientation (pronation vs. supination) was altered too. Therefore, the benefit of WP over NS on LD activation could arise from grip width, forearm orientation, or some combination of the 2. Therefore, the goal of the current study was to resolve this dilemma by comparing all 4 possible combinations of grip width and forearm orientation in a fully balanced design: WP, wide supinated (WS), narrow pronated (NP), and NS. These combinations have not been previously tested, we only hypothesize that WP will activate LD more than NS. This study will also assess MTand BB, because these muscles are also believed to be trained during an LPD (9,10,14).

 

METHODS

 

Experimental Approach to the Problem

 

Although the anteriorWPgrip has been recommended as the most effective and safest type of LPD (12), it is not clear whether this is because of the particular grip width or forearm orientation used, as previous studies have confounded these variables. The current study employed a balanced design to compare grip width (wide vs. narrow), forearm orientation (pronated vs. supinated), and any interaction, by testing WP, WS, NP, and NS anterior grips. The sequence of these conditions was randomized in an effort to negate any possible effects of practice or fatigue. To normalize grip width for different sized individuals, we standardized the grip width based on anthropometric measures. As with previous research, the biacromial diameter was used as the narrow grip width (10,12). There is no standard width for a wide grip. One study employed 150% of biacromial diameter (10), whereas another used the distance from the fist to the seventh cervical vertebrae (12). In an effort to use an anthropometric measure that relates to a wide-grip LPD, we employed _carrying width. This is the distance between the hands (left to right fifth metacarpophalangeal joint) when standing in the anatomical reference position. A standard LPD bar was used for all grips. To standardize the weight across conditions, 70% of 1RM was determined from participants performing a test of 1RM according to ACSM guidelines (1) at least 48 hours before testing. Because a previous study (12) found no significant difference for 10RM between WP and NS grips (,1 kg), we used a single 1RMtest. Although the LPD is primarily used to develop the LD, it is also performed to train the MT and BB (9,10,14). Therefore, EMG signals were recorded from the LD, MT, and BB muscles. In accordance with previous research, the root mean square of each EMG signal (rmsEMG) was employed to quantify the average muscle activity (10,12,15). The rmsEMG for each participant and condition was then normalized to the rmsEMG of an isometric MVC. The normalized rmsEMG was then compared across conditions by using a 2 3 2 (width 3 orientation) repeated-measures analysis of variance (ANOVA) separately for each muscle.This experimental design permits an empirical test of which combination of grip width and forearm orientation elicits the most activity in the LD, MT, and BB.

 

Subjects

 

Participants were 12 men aged 19–30 with an average age = 22.7 ± 3.1 years. The participants’ average mass was 85.86 ± 11.94 kg, and their average height was 1.82 ± 0.10 m. The average biacromial diameter for all participants was 0.40 ± 0.03m, and the average carrying width was 0.76 ± 0.06 m.The average 1RM for all participants was 99.46 ± 19.58 kg. Participants were all free of known musculoskeletal problems of the upper body. This study only examined participants who were previously familiar with the LPD lift and currently lifted weights on a regular basis but were not competitive bodybuilders, weightlifters, or powerlifters. All subjects were tested during the 2008 fall semester at the Berks Campus

of Pennsylvania State University. The Institutional Review Board for the use of human subjects of the Pennsylvania State University granted permission for this study. Participants signed an informed consent after being informed of the experimental risks of the study and before any data collection.

 

Equipment

 

Participants used a standard lat bar on the LPD station of a 4-Stack Multi-Jungle weight machine (Model SM40; Life Fitness, Schiller Park, IL, USA). An auditory quartz metronome (Model XB700; Franz Mfg. Co. Inc., East Haven, CT, USA) was used to provide a consistent cadence throughout the study. Disposable Ag–AgCl pregelled snap electrodes (EL501; BIOPAC Systems, Inc., Goleta, CA) were placed in pairs over the skin, and parallel to the fibers, of the LD, MT, and BB muscles. The LD electrodes were positioned obliquely (25_ above the horizontal) and 0.04 m below the inferior angle of the scapula (6). The MT electrodes were placed 0.03 m lateral to the second spinous process of the thoracic spine with the electrodes placed parallel to muscle fibers (5). The second thoracic vertebra was located by palpating for the seventh cervical vertebrae and counting the spinous processes in a descending fashion until the second

thoracic vertebrae was located and marked. If differentiating the seventh cervical vertebrea was problematic, the participant was instructed to bend the head forward to differentiate the most prominent cervical vertebrea from the first thoracic vertebra (13). The BB electrodes were placed one-third the distance from the cubital fossa to the acromion process (17). Ground electrodes were placed on the acromion process (1 electrode) and the spine of the scapula (2 electrodes). The skin sites were initially prepared by shaving the hair and abrading the skin, before cleaning with an alcohol swab. The distance between the electrode centers was standardized at 0.0375 m. Three shielded lead sets (SS2; BIOPAC Systems Inc.) connected the electrodes to a 4-channel remote monitoring system (TEL100M-C; BIOPAC Systems Inc), which has an impedance of 2 MV and a common mode rejection ratio of 110 dB. All of the leads were taped in place with a loop on the skin and further secured with an elastic bandage around the participant’s torso and upper arm to reduce interference and were examined for stability during a simulated pull-down. The remote monitoring system was connected to a data acquisition and analysis system (MP100; BIOPAC Systems Inc.). The experimenters controlled data acquisition and postprocessing via AcqKnowledge software (version 3.7.3 for Windows; BIOPAC Systems Inc.) running on a microcomputer. Data were collected at a sampling rate of 500 Hz, and the raw EMG signals were amplified by a gain

set at 1,000.

 

Procedures

 

During the initial visit, the following anthropometric measurements were taken: height, weight, biacromial diameter, and carrying width. Biacromial diameter was measured from the lateral aspect of the left to the right acromion processes using anthropometric tape. Carrying width was measured by asking the participants to stand with the palm of their hands facing the sides of their legs. Then the participants were asked to supinate their radioulnar joints so that the palms faced forward, whereas the humeri were maintained beside the body (similar to the anatomical reference position). From this position, the carrying width was measured from the left fifth metacarpophalangeal joint to the right fifth metacarpophalangeal joint, using anthropometric tape. The carrying width was used as the wide grip (W), whereas the biacromial diameter was used as the narrow grip (N) in this study. After recording the anthropometric measures, the exercise protocol was described. Although participants were familiar with an LPD exercise, the specific technique, inhalation and exhalation rhythm for lifting, and metronome pacing were prescribed. After ensuring that participants were comfortable performing the LPD as directed, a 1RM test was performed according to ACSM guidelines (1). The grip width for the 1RM was standardized with all participants placing the second phalanx on each hand at the bend in the bar with a pronated grip. The EMG testing session took place at least 48 hours after initial testing, and the participants were instructed not to exercise until final testing was completed. The EMG equipment was set up and zeroed before being connected to the electrodes that were placed on each participant. The participants performed the 4 conditions (WP, WS, NP, and NS) in a random order, using 70% of 1RM load. The cadence of 2-second concentric and 2-second eccentric phases was prescribed by an auditory beep and visual flash of a metronome. Participants performed 2 trials of 5 repetitions for each condition before moving onto the next, with a 2-minute rest between each trial and condition. The participants were again instructed visually and verbally how to perform an LPD. The thigh restraint pads were adjusted so the thigh and leg formed a 90_ angle with the feet flat on the floor (8). The participants were instructed to be slightly extended at the hips to prevent any collisions with the bar and head and to pull the lat bar down in a straight vertical plane from a slightly flexed position to the participant’s chin in a slow and controlled manner (9). The lat bar was lowered for them, and they remained seated for the entire testing session. Participants started with the elbows slightly flexed and the bar pulled down to the chin for all conditions. Although this meant the amplitude of the movements was not identical across conditions, it ensured the lifts were functionally equivalent. The movement was initiated with scapular depression and retraction, which was held throughout the length of the repetitions until the bar reached the resting position (4,9). The participants were then instructed to begin performing the lifts. The participants were told not to pause at each metronome beep, but slowly transition between the lifting and lowering phases, and requested to inspire on the eccentric, and expire on the concentric muscle actions. With participants performing the LPD correctly and at the right tempo, 5 repetitions were recorded, making up a 20-second trial. If a participant failed to perform correctly, the trial was repeated after a 2-minute rest. After testing all conditions, participants performed an isometric maximum exertion. The isometric exercise was an LPD with the shoulders abducted p/2 rad and both elbows flexed p/2 rad. Participants placed the second phalanx on each hand at the bend in the bar, with a pronated grip, as done for the 1RM test.

 

Electromyographic Analyses

 

For each trial and muscle, the raw EMG signal was amplified by a gain of 1,000 and filtered using a 10-Hz high pass filter (PE). The filtered EMG signal was then smoothed and rectified by calculating the root mean square (rmsEMG) for a 30-data sample moving window (0.06 seconds). The average rmsEMG was then computed for the 2 20-second trials under each condition. The raw EMG signal for each muscle during the maximal isometric contraction was processed in the same way as above, except that an average was computed for only 1 second of maximal activity to avoid effects of fatigue. To normalize the data (normalized root mean square of each EMG signal [NrmsEMG]), the average rmsEMG for each condition was divided by the average rmsEMG for the maximal isometric contraction.

 

Statistical Analyses

 

Normalized root mean square of each EMG signal was analyzed separately for each muscle by 32 x 2 (Width x Orientation) repeated-measures ANOVAs. All statistical procedures were performed using SPSS statistical software version 15.0 (SPSS Inc., Chicago, IL, USA), and the alpha level was selected as p £ 0.05. Intraclass correlation coefficients (ICCs) were computed for NrmsEMG of each muscle separately. All 3 dependent variables indicated strong consistency (ICC 0.87, 0.85, and 0.76 for LD, MT, and BB muscles, respectively).

 

RESULTS

 

No significant difference was found for LD activity between the wide and narrow grips (p =0.711, power = 0.064). In contrast, there was a significant main effect for forearm orientation on NrmsEMG of the LD (p = 0.012, power = 0.776). The LD demonstrated greater activation during a pronated hand grip (M= 0.67) than a supinated hand grip (M = 0.63) (see Figure 1 and Table 1). The interaction of grip width and hand orientation had no significant effect on LD activation (p = 0.185, power = 0.253). The statistical analyzes of the NrmsEMG of MT and BB muscles revealed no significant main effects or interactions (see Table 1).

 

DISCUSSION

 

In agreement with previous literature, a WP grip LPD elicited greater LD muscle activity than an NS grip LPD (12,15). However, our findings indicated this was because of using a pronated forearm orientation, not a wide grip width as proposed by others (12,15). Previous studies based their conclusions by comparing WP with NS, so that the results obtained could have been because of grip width, forearm orientation or a combination of the 2. To avoid this concern, we employed a fully balanced design to compare WP, WS, NP, and NS conditions. In contrast with prior recommendations, grip width did not significantly influence the LD, and neither was an interaction of grip width and orientation observed. The only significant finding indicated that the LD was more active under a pronated grip than a supinated grip. Hence, our results for identical conditions match previous studies of an isotonic LPD (12,15). The only findings they contradict are those for an isometric LPD, which found no differences in the LD between WP and NS grips (10). It would seem that results from an EMG analysis of isometric muscle actions are not necessarily applicable to an isotonic exercise. The different types of grip failed to significantly influence the EMG data for the MT and BB muscles. These findings agree with an earlier study that compared WP with NS and failed to observe any significant difference in muscle activation (10), but as noted above, those findings were based on an isometric LPD. It might have been predicted that with a supinated grip the BB has a more efficacious angle of pull, but there is no training advantage for the BB between the different types of grip tested. It is also useful to look at the amount of NrmsEMGfor each muscle, which indicates the proportion of maximum activity and therefore provides an estimate of the relative activity of each muscle. On average, the LD was activated at 65% of an isometric MVC, whereas the MT and BB were activated at 55 and 42%, respectively. Because the LPD was performed using a load of 70% 1RM, these results would indicate that the LD was being activated at appropriate training levels. In contrast, it would seem that both the MT and BB were activated at lower levels. This suggests that all 4 grip types primarily activated the LD, and to a lesser extent the MT and BB. Therefore, an LPD is best employed to strengthen the LD and is not an optimal exercise for developing the MT or BB muscles. We hypothesize that the LD is more active during a pronated grip vs. a supinated grip because of a greater joint moment at the shoulder. Previous research has suggested that a WP grip involves greater abduction and horizontal abduction than an NS grip, which in turn leads to more LD activity (12). However, the finding here that grip width had no significant effect on the electrical activity of the muscles contradicts this proposal. With the LD being less active during a supinated grip, it might be expected that other muscles would compensate by being more active. Surprisingly, both MT and BB were active at similar levels for all 4 grips. Also, in another EMG study, which compared WP and NS grips, none of the muscles (pectoralis major, posterior deltoid, triceps brachii, and teres major) assessed were more active during an NS grip. These findings suggest that a pronated grip places the shoulder at a mechanical disadvantage that requires greater LD activity but does not affect the MT or BB muscles. A biomechanical analysis of joint moments during a pull-up (2) provides an explanation for our results. The analysis revealed that using a pronated grip leads to a larger overall perpendicular distance between the shoulder joint and pull-up bar than a supinated grip, causing a greater joint moment at the shoulder. In addition, the wrist and elbow joints, and shoulder girdle were not found to be significantly involved during the pull-up, nor were they influenced by the forearm orientation. Because the pull-up is similar to the LPD, we propose that a pronated LPD grip creates a larger joint moment at the shoulder than a supinated grip, which in turn requires greater LD activity to lift the same load.

 

PRACTICAL APPLICATIONS

 

With the main goal of an LPD being to develop the LD muscles, it is important to know which variation best activates this muscle. The findings from this study indicate that a pronated grip is optimal for training the LD in an anterior LPD. Contrary to the claim that a wide grip is best (12,15), the findings here show that there is no difference between narrow and wide grip widths with a pronated grip orientation. Prior research has identified safety concerns and reduced LD muscle activity for a posterior LPD (12). Taking these results together, we conclude that an anterior LPD with a pronated grip is recommended for safely and optimally training the LD, irrespective of the grip width (either carrying width or biacromial diameter). Although the MTand BB were active at similar levels for the different grip types of LPD, other exercises are likely to better train these muscles.

 

ACKNOWLEDGMENTS

This study was funded by a Division of Science Undergraduate

Research Grant, The Pennsylvania State University

Berks, Reading, PA.

 

REFERENCES

1. American College of Sports Medicine. ACSM’s Guidelines for Exercise

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analysis. J Electromyogr Kinesiol 15: 418–428, 2004.

6. Escamilla, RF, Babb, E, Dewitt, R, Jew, P, Kelleher, P, Burnham, T,

Busch, J, D’Anna, K, Mowbray, R, and Imamura, RT. Electromyographic

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7. Funk, DA, An, KN, Morrey, BF, and Daube, JR. Electromyographic

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8. Graham, JF. Front lat pulldown. Strength Cond J 25: 42–43, 2003.

9. Lantz, J andMcNamara, S.Modifying the latissimus pull-down exercise

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16: 539–546, 2002.

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Answering YOUR questions…

Question 1: What’s your advice on obtaining the smallest waist possible for my body?

  • Diet, Diet, Diet!

Question 2: Can I build muscle and lose fat at the same time?

  • Yes and No. I say no because in order to lose fat you have to cut back on how many calories you consume and in order to build muscle you have to increase how many calories you consume on a daily basis. But studies have shown that with the proper weight training and nutrition you can build muscle while you burn fat. This has been proven true with a lot of track athletes because of high intensity interval training along with a high intensity resistance program.

Question 3: Just how much protein do I need?

  • Protein needs are usually based on what your goal is. But the usual formula is 1g of protein times your body weight ex: 1g x 128 = 128g of protein per day.

Question 5: What are some examples of good HIT workouts?

Here are a few HIT workouts that I do myself:

HIT #1

  • Shoulder Press
  • Crunches
  • Standing Calf Raises
  • Barbell Curls
  • Bench Press
  • Lying Leg Curls
  • Bent Over Row
  • Seated Calf Raises
  • Squats
  • Reverse Crunches
  • Straight Arm Pullovers
  • French Presses
  • Deadlifts
  • Upright Rows
  • Crunches
  • Wrist curls

 

HIT #2

  • Deadlift 1 x 10-12
  • Leg Press 1 x 10-12
  • Shrug 1 x 8-10
  • Close Grip Lat Pulldown 1 x 8-10
  • Standing Calf Raise 1 x 10-15
  • Reverse Curls 1 x 10-15
  • Overhead Press 1 x 8-10
  • Abs 1 x 30-50

Question 6: How much rest do we need between workouts?

  • Rest between workouts is all dependent upon the person. I personally take 2 days off after I do 4 days straight. After I take those 2 days off I cycle my workouts and start again. To answer your question: Just listen to your body.

Nutrition For Recovery

Athletes are always seeking ways to enhance performance and delay fatigue. Muscle glycogen is the major fuel source during prolonged, moderate to high-intensity exercise, and there is a direct relationship between depleted muscle glycogen and fatigue. Therefore, muscle glycogen repletion is vital to recovery time and maintaining top performance for athletes at all levels (1). Glycogen repletion is important to ensure an athlete’s quick muscle recovery for subsequent practices, especially those who train, or must compete, multiple times in a single day (1). Timing, composition and the quantity of a post-exercise meal or snack is dependent upon the length and intensity of exercises, timing of the next exercise session, as well as an individual’s needs (1).

Carbohydrates For Recovery—

How Much?

The current recommendation for daily carbohydrates (CHO) consumption is 5 – 7g CHO/kg/day for the general athlete and 7 – 10g/kg/day for the endurance athlete (1). Consuming CHO immediately after exercise accelerates glycogen repletion (10) because there is increased blood flow to the muscles, which results in heightened sensitivity to insulin (9). Sufficient CHO ingestion over the next 24 hours is also important. Current recommendations are to consume 1 – 1.5g of CHO/kg of body weight within 30 minutes after exercise and then again at 2-hour intervals for the next six hours (1). See Table 1 for some ideas on what to consume within 30 minutes post-exercise.

Carbohydrates For Recovery—

What Type?

The type of carbohydrate (CHO) an athlete consumes after exercise can affect how much and how quickly he or she resynthesizes glycogen. Foods and/or beverages containing glucose/ sucrose, and those having a high glycemic index are preferred. Glucose and sucrose are preferred over fructose (1), as fructose promotes a lower level of glycogen resynthesis as compared to glucose (3) and larger amounts of fructose may promote gastrointestinal distress due to its slower absorption rate(3). High glycemic index foods induce higher muscle glycogen levels as compared to low glycemic index foods (1). Readily available foods, such as whole grain cereal and skim milk, have been found to be an effective post-exercise fuel (2). In fact, one study found that the carbohydrate to protein combination found in a bowl of whole grain cereal and skim milk had a similar effect on muscle glycogen repletion as did sports drinks (2). The combination was also found to positively affect protein synthesis. From this research, it seems that whole foods can be a good alternative to commercial sports drinks, if preferred by the athlete.

Endurance exercise

Endurance athletes may benefit from consuming protein along with carbohydrates after exercise as this combination has been shown to reduce markers of muscle damage and improve post-exercise recovery. This could also have a positive effect on subsequent performances (8). Some studies have demonstrated a benefit of Branched Chain Amino Acids (BCAA) on muscle recovery (6). BCAA’s appear to affect muscle protein metabolism during and after exercise and prevent muscle damage induced by exercise (6). The release of amino acids from muscles is decreased when BCAA’s are ingested (6).

Resistance Exercise

The goal for athletes in resistance-type exercise is to increase muscle mass and strength. The nutrition intervention for this type of activity involves stimulating net muscle protein gains during recovery. PRO ingestion increases the rate of muscle protein synthesis and inhibits protein breakdown after training (10). One study found that during prolonged resistance training, post-exercise consumption of CHO and PRO, 1 – 3 hours after resistance training stimulated improvements in strength and body composition better than a placebo (3). Essential amino acids in a dose of 40g have regularly shown to have an effect in promoting muscle protein synthesis and CHO may enhance this effect (3). The findings suggest ingesting 50 – 75g CHO with 20 – 75g PRO after heavy resistance training (3). Furthermore, adding 10g of creatine has shown to produce a significant increase in body mass as compared to just CHO and PRO (3). See Table 2 for possible CHO and PRO combinations.

Bottom Line

Nutrition post-exercise has been proven to promote recovery for athletes. Post-exercise nutrition has been shown to increase strength and muscle mass in athletes who participate in resistance-type exercises. Timing, composition and amount of post-exercise food is dependent upon the individual, timing of the next exercise session and the activity performed. 

References

1. American Dietetic Association. Position of the American Dietetic

Association, Dietitians of Canada, and the American College of Sports

Medicine: Nutrition and athletic performance. Journal of the American

Dietetic Association. 2009(109).

2. Kammer L, Ding Z, Want B, Hara D, Liao Y, Ivy J. Cereal and nonfat milk

support muscle recovery following exercise. Journal of the International

Society of Sports Nutrition. 2009(6).

3. Kerksick C, Harvey T, Stout J, Campbell B, Wilborn C, Kreider R,

Kalman D, Ziegenfuss T, Lopez H, Landis J, Ivy J, Antonio J. International

Society of Sports Nutrition position stand: Nutrient timing. Journal of the

International Society of Sports Nutrition. 2008(5).

4. Miller SL, Gaine PC, Maresh CM, Armstrong LE, Ebbeling CB, Lamont

LS, Rodriguez NR. The Effects of Nutritional Supplementation Throughout

an Endurance Run on Leucine Kinetics During Recovery. International

Journal of Sport Nutrition and Exercise Metabolism. 2007(17).

5. Mizuno K PhD, Tanaka M PhD, Nozaki S PhD, Mizuma H PhD, Ataka

S MD, Tahara T PhD, Sugino T MSc, Shirai T MSc, Kajimoto Y PhD,

Kuratsune H PhD, Kajimoto O PhD, Watanabe Y PhD. Antifatigue effects

of coenzyme Q10 during physical fatigue. Applied Nutritional Investigation.

2007.

6. Negro M, Giardina S, Marzani B, Marzatico F. Branched-chain amino acid

supplementation does not enhance athletic performance but affects muscle

recovery and the immune system. Journal of Sports Medicine and Physical

Fitness. 2008(48).

7. Rowlands D, Thorp RM, Rossler K, Graham DF, Rockell MJ. Effect of

Protein-Rich Feeding on Recovery After Intense Exercise. International

Journal of Sport Nutrition and Exercise Metabolism. 2007(17).

8. Saunders, Michael J. Coingestion of Carbohydrate-Protein During

Endurance Exercise: Influence on Performance and Recovery. International

Journal of Sport Nutrition and Exercise Metabolism, 2007(17).

9. Stout, Andrew. Fueling and Weight Management Strategies In Sports

Nutrition. Journal of the American Dietetic Association. 2007(07).

10. Van Loon, Luc J.C. Application of Protein or Protein Hydrolysates to

Improve Postexercise Recovery. International Journal of Sport Nutrition and

Exercise Metabolism. 2007(17).

Taken from: NSCA’s Performance Training Journal Volume 9, Issue 2

February is Here!!

February is National Heart Month. Not because it’s Valentines day but because we need to become more aware of Heart Disease.

Here are some facts:

  • About every 25 seconds, an American will have a coronary event
  • Most common heart disease is coronary heart disease
  • In 2010, an estimated 785,000 Americans had a new coronary attack, and about 470,000 had a recurrent attack
  • These conditions put your health at risk of death or disability: arrhythmia, heart failure, peripheral artery disease (PAD), high cholesterol, high blood pressure, obesity, diabetes, tobacco use, unhealthy diet, physical inactivity, and secondhand smoke

It’s time you start helping the people you care about make healthier choices and try to start putting them on a path to a healthier lifestyle. Diet and exercise play a major part.

If you want more information regarding Heart Disease and more about National Heart Month check out: cdc.gov/features/heartmonth

In 2006 there was research published in the International Journal of Sport Nutrition and Exercise Metabolism trying to see if you could use Chocolate Milk as a recovery aid versus a Carbohydrate replacement drink (i.e. Gatorade). Results of this study shows that Chocolate Milk can be used and is an effective recovery aid. I have attached the article for your viewing pleasure. It’s about 15 pages but it’s worth reading.

Chocolate Milk as a Post-Exercise Recovery Aid

Chocolate milk (CM) offers many benefits besides being an effective post-exercise recovery aid.

  1. Chocolate has caffeine which can help decrease fatigue after a long workout
  2. Chocolate itself contains tryptophan which is an essential amino acid aiding in the production of serotonin, a natural stress reducer, and enables the body to relax.
  3. Chocolate milk also contains vitamin A (linked to fighting heart disease), B (converts carbohydrates into glucose which enables you to have more energy), D (CALCIUM DUH!!!), and E (protect against skin cancer and strengthen the skin’s barrier function)

So as you can see CM has great health benefits. Try it out sometime as a substitute.

  1. .

I was going through my notes from an Anatomy and Physiology course I took. Thought I would share.

Effects of Training

Hypertrophy may produce new fibers due to fiber splitting (hyperplasia) in response to certain workloads; not due to entirely new cell production in response to exercise.

Training does NOT produce major shifts in muscle fiber types. Training may alter the metabolic capabilities of muscle fibers (but not the contractile properties), and there remains the possibility that this alteration could be significant enough to change the classification of the FT fibers; fast-twitch fibers may shift from fast glycolytic to fast oxidative glycolytic and vice versa.

Training – results in muscle fiber hypertrophy and may change some fast twitch fiber types, but these changes, as well as increased endurance and increased number of capillaries, ARE reversible when use is discontinued.

If training stops, capillary networks shrink, the number of mitochondria in muscle fibers decreases, the number of actin and myosin filaments decreases, and the muscle atrophies.

Muscular Fatigue

Fatigue => a transient loss of work capacity resulting from preceding work; inability of muscle to contract forcefully after prolonged activity. Fatigue limits performance in normal conditions and even more so in disease.

Fatigue results in the cessation of muscular work or the inability to maintain a given intensity of work.

Muscular fatigue is a complex phenomenon that includes failure at one or more of the sites along the chain of events that leads to muscular contraction.  Fatigue can be classified as central or peripheral on the basis of the location of the site of fatigue.

Peripheral fatigue refers to fatigue at a site beyond the central nervous system; this may include sites within the peripheral nervous system or within the skeletal muscle.  Peripheral fatigue can occur at several sites; the neuromuscular junction, the sarcolemma-T tubules-sarcoplasmic reticulum system, and the myofilaments.

Muscle Fatigue

A muscle exercise strenuously for a prolonged period may lose its ability to contract = fatigue. Fatigue is the transient loss of work capacity resulting from preceding work.

Fatigue is usually the result of the accumulation of lactic acid in the muscle as a result of anaerobic respiration.  The lactic acid buildup lowers pH, and as a result, muscle fibers no longer respond to stimulation.  Also, there is a build-up of certain metabolites, which impair force production such as hydrogen, ammonia, and phosphate. Fatigue can also result from the accumulation of certain metabolites, which impair force production, such as hydrogen, ammonia, and phosphate.

A muscle may become fatigued and cramp simultaneously.

Cramp = spasmodic muscle contractions in which the muscle is not allowed to relax completely between contraction. Cramping is the result of a lack of ATP, which is required to return calcium ions to the sarcoplasmic reticulum and the break the linkages between the actin and myosin filaments before the muscle fibers can relax.

Strain – minimal to moderate tearing of the muscle fibers and possible associated connective tissues due to overstretching.

Muscular Soreness

There are two generally recognized types of muscle soreness.  One type of muscular soreness is characterized by pain during and immediately after exercise, which may persist for several hours.  The second type of muscular soreness is characterized by a local pain, which appears 24-48 hours after exercise and may persist for 7 days postexerciseThe pain experienced during and immediately exercise is thought to be caused by stimulation of the pain receptors by metabolic by-products of cellular respiration. Such pain is generally relieved by discontinuing exercise, or it subsides shortly thereafter. The second type of soreness is called delayed-onset muscle soreness (DOMS). This soreness increases in intensity for the first 24 hours after activity, peaks from 24-48 hours, and then declines during the next 5-7 days.

The causative factors and cellular mechanisms of DOMS remain elusive.  There are, however, several theories that have attempted to integrate the findings of research on this topic.  Two of the primary theories of DOMS are the mechanical trauma theory and the local ischemic theory.  These theories are not mutually exclusive; on the contrary, they share many of the same elements.

Etiology and Mechanisms

The mechanical trauma model (Armstrong) proposes to describe the mechanisms responsible for DOMS.  As the name implies, this model suggests that the mechanical forces in the contractile or elastic tissue result in structural damage to the muscle fibers.  Damage to the sarcolemma of the cell leads to disruption in calcium homeostasis, which results in necrosis (death of tissue).  The presence of cellular debris and immune cells (macrophages) leads to swelling and inflammation, which is responsible for the sensation of DOMS.

The local ischemic model (DeVries and Housh) suggests that exercise – even moderate, atraumatic activities-causes swelling the muscle tissue, which increases tissue pressure. This increase in tissue pressure is thought to result in local ischemic (reduced blood flow), which causes pain and lead to tonic muscle constriction (spasm).  This spasm causes additional swelling and perpetuates a cycle of swelling and ischemia that results in the painful sensation known as DOMS.  It is suggested that local ischemia can result in structural damage that leads to inflammation and swelling, and thus, exacerbates the cycle.

While there is considerable overlap in mechanisms proposed by the two models, the major distinction between the models is the event that initiates the cycle. It is possible that both models are viable.  DeVries points out that overexertion involving long-duration and moderate-intensity activities leads to DOMS.  On the other hand, Armstrong concentrates on the manifestation of DOMS after activities that place considerable mechanical force on the muscle, specifically, eccentric contractions that are known to cause DOMS.

One of the popular concepts – rather misconceptions- regarding DOMS is that is caused by the accumulation of lactic acid. Although this theory was proposed by researches, there is now considerable evidence to argue against this theory, including the facts that individuals who have McArdle’s syndrome and do not produce lactic acid also suffer from DOMS.  Additional evidence against lactic acid as the cause of muscle soreness is that the type of activity that produced the greatest degree of soreness, namely eccentric contractions, produces lower lactic acid levels than concentric contractions of the same power output. Perhaps the most compelling evidence is that lactic acid has a half-life of 15-25 minutes is fully cleared from muscle within an hour.  Since lactic acid is not present (at least not at elevated levels) it cannot cause soreness 24-48 hours later.

What is pain?

I feel like being a nerd right now 🙂

Pain is defined by the IASP as “an unpleasant physical and emotional experience which signifies tissue damage or the potential for such damage”  The transmission of the pain sensation occurs on many different levels: periphery, spinal level, ascending pathway, supraspinal level, or descending pathway.

Peripheral sensory receptors contain two types of receptors: superficial and deep tissue receptors. The peripheral sensory receptors provide the central nervous system with information about pain, touch, vibration, temperature, and proprioception. Superficial receptors transmit sensations such as warmth, cold, touch, pressure, vibration, tickle, itch, and pain from the skin. Deep receptors transmit information regarding position, kinesthesia, deep pressure, and pain from the muscles, tendons, fascia, joint capsules, and ligaments.

Superficial receptors are subdivided into three categories based on the type of stimuli they respond to.

  • Mechanoreceptors
  • Thermoreceptors
  • Nociceptors

Mechanoreceptors respond to pressure, stroking, and touch. Thermoreceptors respond to temperature and temperature change. Nociceptors are also called free nerve endings and are stimulated by mechanical, chemical, and thermal stress. Nocicepors are sensitized by prostaglandins, bradykinin, substance P, serotonin and other chemical mediators of inflammation or by pressure and distension.

Deep sensory receptors identify changes in muscle length, muscle spindle tension, change in joint position, vibration, joint end range, etc.

Afferent sensory nerves are when impulses that were generated at the sensory receptors and are transmitted to higher centers. Afferent nerves are classified according to their structure and function. These nerves are grouped by diameter or width of the nerve, the degree of myelination, and the nerve’s function. The myelinated nerves are: A-beta and A-delta and the information that is transmitted is: touch, vibration, pressure, temperature, and pain. These nerves are located on the skin and originate from your hair follicles. A-delta fibers transmit information from warm and cold receptors The unmeylinated nerve is C and transmits pain, touch, pressure, temperature, and pain. The C fibers are the smallest peripheral nerves that are associated with pain. They (C-fibers) are the slowest of the sensory nerve fibers in conduction and require a greater stimulation than the others to elicit a response.

Once the afferent peripheral nerves enter the spinal cord, it synapses in the dorsal horn. Multiple pathways or tracts carry sensory input to the brain. The thalamus is the target for the second-order neurons in both pleasant and noxious sensory input in the supraspinal centers. Ultimately, the localization and discrimination of pain occur in the postcentral gyrus of the cortex of the brain. The thalamus also relays sensory input that provides for the sensory-discriminatory and affective-motivational aspects of pain.

The descending pathways ultimately have an excitatory or inhibitory action on new impulses that are being transmitted in the spinal cord.

As you can see your body has a way of processing pain especially the sensations that you feel and how they are perceived. The question is: how high is your threshold for pain?