High-Density Electromyography Excitation in Front vs. Back Lat Pull-Down Prime Movers

The current study compared the spatial excitation of the primary muscles during the lat pull-down exercise with the bar passing in front (front-LPD) or behind the neck (back-LPD) using high-density electromyography. Fourteen resistance trained men performed a front-LPD or a back-LPD within a non-fatiguing set with 8-RM as the external load. The muscle excitation centroid of latissimus dorsi, middle trapezius, pectoralis major, biceps brachii, triceps brachii and posterior deltoid muscles were recorded during the ascending and the descending phase. During the descending phase, the front-LPD showed superior excitation of the latissimus dorsi (ES = 0.97) and the pectoralis major (ES = 1.17), while in the ascending phase, the back-LPD exhibited superior excitation of the latissimus dorsi (ES = 0.63), and the front-LPD showed superior excitation of the biceps brachii (ES = 0.41) and the posterior deltoid (ES = 1.77). During the descending phase, the front-LPD showed a more lateral centroid of the latissimus dorsi (ES = 0.60), the biceps brachii (ES = 0.63) and the triceps brachii (ES = 0.98), while the centroid was more medial for the middle trapezius (ES = 0.58). The centroid of the middle trapezius was also more medial in the front-LPD during the ascending phase (ES = 0.85). The pectoralis major centroid was more cranial in the front-LPD for both the descending (ES = 1.58) and the ascending phase (ES = 0.88). The front-LPD appears to provide overall greater excitation in the prime movers. However, distinct spatial excitation patterns were observed, making exercise suitable for the training routine.

Isometric Strength Database for Muscle Maximal Voluntary Endurance Field Tests: Normative Data

Background

Different field tests are used to evaluate muscle capacity, in particular maximal voluntary isometric endurance. However, although there are some normative values for a few muscle endurance tests, these do not consider the weight, height, gender, or age of individuals, which are well-known factors that influence muscle performance.

Hypothesis/Purpose

The purpose of this study was to investigate the test–retest reproducibility of eight field tests and establish muscle endurance norms, in a healthy population, based on their anthropometric characteristics, which could allow the optimal evaluation of the entire muscle function in a quick manner.

Design

Case series.

Methods

This study was conducted in two phases. The first phase was to check the reproducibility inter- and intra-assessor for eight isometric muscle field tests on 20 volunteer subjects aged 40.9 ± 11.6 years old (age range, 21–58 years). The second part was to establish muscle maximal voluntary isometric endurance norms according to these tests on a total of 400 healthy participants grouped by age (50 males and females in each of the age brackets, 20–29; 30–39; 40–49; 50–59 years old, for a total of 200 males and 200 females).

Results

The intra- and inter-assessor reproducibility tests are good for all muscle measurements (the intraclass correlation coefficients varied between 0.915 and 0.996 and the coefficient of variation between 3.6 and 11.8%). The area under the receiver operating characteristic curves demonstrates a good sensibility with values greater than 0.7 for each test. Each muscle belt presents same ratio regardless of the age and gender group. The simultaneous multiple regression analyses highlight that the anthropometric characteristics of subjects influence significantly the performance of isometric tests.

Conclusion

This study has permitted establishing prediction equations in a healthy population according to their anthropometric characteristics as well as agonist/antagonist ratios for eight muscle isometric field tests after demonstrating a good reproducibility of all tests.

Electromyographical Comparison of a Traditional, Suspension Device, and Towel Pull-Up

Strengthening muscles of the back may have various implications for improving functions of daily living, aiding in the transfer of power in throwing, and assist in injury prevention of the shoulder complex. While several versions of the pull-up exist, there is currently no literature comparing their differences. The purpose of this investigation was to compare the electromyographical activity of the latissimus dorsi, posterior deltoid, middle trapezius, and biceps brachii while performing three variations of the pull-up. Resistance-trained men and women (n =15, age = 24.87 ± 6.52 years) participated in this study by performing traditional pull-ups, suspension device pull-ups, and towel pull-ups in a randomized fashion. Each pull-up was performed for three repetitions with a 1.5 bi-acromial grip-width for each participant. Normalized (%MVC) electromyographical values were recorded for each muscle group during each pull-up variation. No significant differences existed within the latissimus dorsi, biceps brachii or posterior deltoid between any of the exercises. For the middle trapezius, towel pull-ups provided significantly lower muscle activity than the traditional pull-up, while no differences between suspension pull-ups and the other variations occurred. In conclusion, only one muscular difference existed between the exercise variations and all versions examined provided electromyographical values, determined by current literature, to invoke a sufficient stimulus to promote increases in muscle strength and hypertrophy. Although further research is needed, practitioners can be confident when programming any of the movement variations examined when attempting to elicit adaptations of muscular strength and hypertrophy.

Nutrition, Pharmacological and Training Strategies Adopted by Six Bodybuilders: Case Report and Critical Review

The purpose of this study was to report and analyze the practices adopted by bodybuilders in light of scientific evidence and to propose evidence-based alternatives. Six (four male and two female) bodybuilders and their coaches were directly interviewed. According to the reports, the quantity of anabolic steroids used by the men was 500–750 mg/week during the bulking phase and 720–1160 mg during the cutting phase. The values for women were 400 and 740 mg, respectively. The participants also used ephedrine and hydrochlorothiazide during the cutting phase. Resistance training was designed to train each muscle once per week and all participants performed aerobic exercise in the fasted state in order to reduce body fat. During the bulking phase, bodybuilders ingested ~2.5 g of protein/kg of body weight. During the cutting phase, protein ingestion increased to ~3 g/kg and carbohydrate ingestion decreased by 10–20%. During all phases, fat ingestion corresponded to ~15% of the calories ingested. The supplements used were whey protein, chromium picolinate, omega 3 fatty acids, branched chain amino acids, poly-vitamins, glutamine and caffeine. The men also used creatine in the bulking phase. In general, the participants gained large amounts of fat-free mass during the bulking phase; however, much of that fat-free mass was lost during the cutting phase along with fat mass. Based on our analysis, we recommend an evidence-based approach by people involved in bodybuilding, with the adoption of a more balanced and less artificial diet. One important alert should be given for the combined use of anabolic steroids and stimulants, since both are independently associated with serious cardiovascular events. A special focus should be given to revisiting resistance training and avoiding fasted cardio in order to decrease the reliance on drugs and thus preserve bodybuilders’ health and integrity.

Biceps Disorder Rehabilitation for the Athlete: A Continuum of Moderate- to High-Load Exercises

BACKGROUND

Progressive biceps loading is recommended in the nonoperative and operative rehabilitation of biceps-related disorders. Previous researchers have proposed a continuum of exercises with low to moderate biceps loads to be used in the early and intermediate phases of rehabilitation. A progression of exercises with moderate to high biceps loads to be used in the more advanced phases of rehabilitation is lacking.

PURPOSE

To describe a progression of exercises with progressive moderate to high loads on the biceps brachii (BB) based on electromyographic (EMG) analysis.

STUDY DESIGN

Controlled laboratory study.

METHODS

The EMG activity of BB and triceps brachii; upper trapezius, middle trapezius, and lower trapezius; and serratus anterior was determined with surface electromyography in 30 asymptomatic participants during 11 exercises.

RESULTS

Of the 11 exercises, 4 (arm shake with an Xco-trainer, lateral pull-down in pronation, chest shake with an Xco-trainer, lateral pull-down in supination) showed low (<20% maximal voluntary isometric contraction [MVIC]), 5 (pull-up in pronation with Redcord, air punch, forward flexion in supination, pull-up in supination with Redcord, inclined biceps curl) showed moderate (between 20%-50% MVIC), and 2 (throwing forward flexion, reverse punch) showed high (>50% MVIC) EMG activity in the BB. These exercises were ranked with an increasing level of activity in the BB.

CONCLUSION

The continuum of exercises with moderate to high biceps activity may be applied in the more advanced phases of treatment for biceps disorders. In addition, biceps muscle activity may be targeted by (1) sagittal plane elevation; (2) elbow flexion with supination, without upper arm support; (3) biceps contraction from an elongated position; or (4) high-velocity, explosive exercises.

CLINICAL RELEVANCE

These findings may assist clinicians to select appropriate exercises to be used in the more advanced phases of nonoperative or postoperative rehabilitation of overhead athletes with biceps-related injuries.

Determination of a strength index for upper body local endurance strength in sedentary individuals: a cross sectional analysis

A range of balance between flexor and extensor muscles is fundamental in order to prevent pathologies caused by bad postures or to ensure health of the joint as a measure of prevention of overtraining in specific muscle groups. Therefore, the aim of this study is to examine the ratio between "pulling" and "pushing" strength in sedentary individuals. 212 healthy participants, of both genders (139 male and 73 female; age 32 ± 13.3 years, weight 70.2 ± 14.1 kg, height 173 ± 9 cm) were retained for investigation. Strength was assessed through a new methodology: Pulling through a lat-pulldown test while pushing strength through a chest-press test. Both tests were performed to exhaustion with an overload of 30 % of each participants bodyweight. Such method aims to prevent excessive overloads in sedentary individuals. Pearson's correlations and a t test to assess differences were analyzed. Subsequently, the ratio for both genders of pulling and pushing local endurance strength was assessed by means. A mean number of 57 repetitions was shown with the lat-pulldown while 34 repetition with the chest press. A correlation of 0.42 has been found between the number of repetitions of the two tests. A significant difference (p < 0.001) was found between such performances. No correlation was found between the strength measures and the anthropometric parameters of the participants. The lat machine to chest press ratio was 1.36:1 for male while 2.69:1 for female. The results indicate that sedentary participants have higher pulling rather than pushing local endurance strength. Such ratio should be considered as a normative value when starting to perform exercise protocols. Resistance training should be performed in order to improve strength measures of the weaker muscles and reduce such ratio.

Effects of pre-exhausting the biceps brachii muscle on the performance of the front lat pull-down exercise using different handgrip positions

The aim of the present study was to investigate the effects of pre-exhaustion (PE) of the biceps brachii muscle (BB) on the number of repetitions and the rate of perceived exertion (RPE) in the front lat pull-down (FLPD) using different handgrip positions. Additionally, the effect of sex and its interaction with performance and the RPE were also examined. The participants were 19 healthy subjects: 8 men (age: 27.13±2.85 years; body height: 180.63±6.65 cm; body mass: 82.05±8.92 kg; and body fat: 14.67±6.09%); and 11 women (age: 28.81±3.68 years; body height: 162.91±6.51 cm; body mass 59.63±6.47 kg; and body fat: 24.11±4.33%). The number of repetitions and the RPE in the FLPD exercise with different handgrip positions, with and without PE of the BB, was documented. The following main significant effects were seen: i) PE of the BB decreased the number of repetitions (p<0.001) and increased the RPE (p<0.001); ii) the narrow handgrip width elicited a higher RPE (p<0.001) and iii) women performed fewer repetitions than men in all FLPD exercise variations (p=0.023). Significant interactions were also observed between: i) PE or sex and the RPE (p=0.024); and ii) PE or handgrip width and the number of repetitions (p<0.001). In conclusion, PE of the BB promotes a decreased performance in the FLPD exercise along with a greater RPE, especially when using a narrow handgrip position.

Effect of the Foot Placements on the Latissmus Dorsi and Low Back Muscle Activities during Pull-down Exercise

[Purpose] The purpose of this study was to examine the effects of foot placement on the latissmus dorsi and low back muscles activities during pull-down exercise. [Subjects] For this study, we recruited 10 male volunteers. [Methods] The subjects performed pull-down exercises with 4 foot placement conditions. The activities of the latissmus dorsi and L4 paraspinal muscles were measured. [Results] The activities of the latissmus dorsi muscles significantly increased in the order of conditions 1 and 2 < condition 4 < condition 3. The activities of the L4 paraspinal muscles were significantly different, with the activities of conditions 1 and 2 being greater than those of conditions 3 and 4. [Conclusion] We suggest that the selection of foot placement is an important factor for the effective strengthening of the latissmus dorsi.

Effects of the Pullover Exercise on the Pectoralis Major and Latissimus Dorsi Muscles as Evaluated by EMG

The aim of the current study was to investigate the EMG activity of pectoralis major and latissimus dorsi muscles during the pullover exercise. Eight healthy male volunteers took part in the study. The EMG activity of the pectoralis major and that of the latissimus dorsi of the right side were acquired simultaneously during the pullover exercise with a free-weight barbell during both the concentric and eccentric phases of the movement. After a warm-up, all the subjects were asked to perform the pullover exercise against an external load of 30% of their body weight, during 1 set × 10 repetitions. The criterion adopted to normalize the EMG data was the maximal voluntary isometric activation. The present findings demonstrated that the barbell pullover exercise emphasized the muscle action of the pectoralis major more than that of the latissimus dorsi, and the higher activation depended on the external force lever arm produced.