Surface EMG during the Push-up plus Exercise on a Stable Support or Swiss Ball: Scapular Stabilizer Muscle Exercise

Strength and activity of the protractor and retractor muscles of the asymptomatic dyskinetic scapula

The role of scapular dyskinesis as a risk factor of shoulder injury has been largely discussed. However, most studies have focused on symptomatic patients and less is known on the asymptomatic dyskinetic scapula. Removing the confounding effects of the pathologies could contribute to better characterize the scapula dyskinesis. As muscle properties (strength, fatigue, nerve injury …) have been identified as causative factors of scapular dyskinesis, this study focuses specifically on characterizing the protractor and retractor muscles of the dyskinetic scapula. Thirteen asymptomatic dyskinetic volunteers were compared to eleven asymptomatic non-dyskinetic control volunteers. Muscle characteristics were evaluated in terms of maximal strength, fatigue resistance and electromyographic activity during a functional closed-chained task. The results did not identify kinematic or muscle activity significant differences between the dyskinetic and the control group even in fatigue conditions. However, the results demonstrated that protractors vs. retractors fatigue resistance ratios were imbalanced (<0.8) in the dyskinetic group and significantly lower than in the non-dyskinetic one. Our study suggests that that strength imbalances are not necessarily related to the presence of pain at the shoulder joint. These results demonstrated the importance to complete the clinical assessments of the scapula with strength evaluations even for asymptomatic sport practitioners.

Electromyography of shoulder muscles in individuals without scapular dyskinesis during closed kinetic chain exercises on stable and unstable surfaces: a systematic review and meta-analysis

Introduction

Unstable surfaces are commonly utilized to enhance the flexibility of the musculoskeletal system for achieving training or rehabilitation goals. However, their effects on shoulder muscle activation during various push-up (PU) exercises have not been thoroughly investigated. Therefore, the purpose of this study was to synthesize electromyography (EMG) data of shoulder muscles in individuals without scapular dyskinesis performing different PU exercises on both stable and unstable surfaces.

Methods

A systematic online search was conducted in electronic databases, including Web of Science, PubMed, Scopus, and Google Scholar, up to January 16, 2024, using predefined sets of keywords. Out of the 1,971 titles and abstracts screened, 80 articles were reviewed in detail by two independent researchers to check the eligibility, of which 28 eligible studies were ultimately included. Following assessment of the quality and risk of bias, the studies were categorized based on exercises and muscle groups, and a meta-analysis using a random-effects model was performed to estimate the overall effect size.

Results

The use of unstable surfaces led to a decrease in anterior deltoid activity during PU [P = 0.032; I2 = 91.34%; SMD = -0.630 (95% CI -1.205, -0.055)], an increase in pectoralis major activity during PU [P = 0.006; I2 = 63.72%; SMD = 0.282 (95% CI 0.079, 0.484)], as well as during knee PU [P = 0.018; I2 = 32.29%; SMD = 0.309 (95% CI 0.052, 0.565)], and an increase in triceps brachii activity during PU [P = 0.000; I2 = 85.05%; SMD = 0.813 (95% CI 0.457, 1.168)], knee PU [P = 0.000; I2 = 0.00%; SMD = 0.589 (95% CI 0.288, 0.891)], as well as during push-up plus [P = 0.006; I2 = 13.16%; SMD = 0.563 (95% CI 0.161, 0.965)]. However, the use of unstable surfaces did not show a significant effect on the EMG activity of the pectoralis major during push-up plus [P = 0.312; I2 = 22.82%; SMD = 0.207 (95% CI -0.194, 0.609)].

Conclusions

Unstable surfaces can modulate muscle activity in different PU exercises, while the effects on the targeted muscles depend on the type of exercise. The findings of this review provide a framework based on the level of activity of each shoulder muscle during different PU exercises, which can help coaches, trainers, and sports therapists select the most suitable type of PU for designing training or rehabilitation programs. Particularly, the most suitable exercise for increasing anterior deltoid activity is PU on a stable surface. To concurrently increase activity of the pectoralis major and triceps brachii, adding unstable surfaces under hands during knee PU and standard PU is recommended.

Systematic Review Registration

PROSPERO, identifier CRD42021268465.

Electromyography of scapular stabilizers in people without scapular dyskinesis during push-ups: a systematic review and meta-analysis

Background: Push-up (PU) is widely considered an effective exercise to stabilize the scapular, especially if performed on unstable surfaces. However, available studies cover a wide range of exercise variations and differ according to exercise prescription, muscle selection and study design. Therefore, findings are contradictory, and conclusions for a proper application of the PU are difficult to draw. Objective: To synthesize the available literature on the changes in the activity of the periscapular muscles in individuals without scapular dyskinesis while performing different types of PU on unstable surfaces. Search procedure: Four online databases were searched from the earliest publications to 9 August 2023, using predefined keywords. Out of the 2,850 potential references identified in the primary search, 92 studies were reviewed in detail, of which 38 met the inclusion criteria and were included. Methodological quality was evaluated using a standardized form based on the Newcastle‒Ottawa scale for observational studies. Data combination was performed using CMA (v3), and the random-effects model was used to calculate the standardized mean difference (SMD) with a 95% confidence interval (CI). Results: The use of unstable surfaces in people without scapular dyskinesis led to increased activity of the upper trapezius during the PU (p = 0.017; I2 = 84.95%; SMD = 0.425 [95% CI 0.077, 0.773]) and knee PU (p = 0.023; I2 = 70.23%; SMD = 0.474 [95% CI 0.066, 0.882]) exercises and increased activity of the middle trapezius (MT) (p = 0.003; I2 = 64.50%; SMD = 0.672 [95% CI 0.225, 1.119]) and serratus anterior (SA) (p = 0.039; I2 = 4.25%; SMD = 0.216 [95% CI 0.011, 0.420]) muscles during the push-up plus (PUP) exercise. Conclusion: Using an unstable support base during PU does not necessarily increase the activity of all scapular stabilizers. The amount of muscle activity depends on the type of PU other than the type of support base. If an unstable surface is used, PUP exercise appears to be the most effective modality to increase the quality of training, improve performance, and prevent the occurrence of scapular dyskinesis due to the increase in the activity of the MT and SA muscles. Systematic Review Registration: http://www.crd.york.ac.uk/PROSPERO, CRD42021268465.

Innovative Use of Biodex Balance System to Improve Dynamic Stabilization and Function of Upper Quarter in Recreational Weightlifters: A Randomized Controlled Trial

Background and Objectives: Following an injury, upper-body strength and proprioception training is typically suggested. To our understanding, no prior research has looked into the impact of balance training on upper-body strength and stability. So, this study investigated the effects of Biodex balance training on enhancing the dynamic stability, strength, and function of the upper quarter (UQ) in recreational weightlifters. Materials and Methods: Fifty male weightlifters were randomly assigned into two groups. The experimental group received an upper-extremity Biodex balance training program three times/week for eight weeks, while the control group underwent a regular weightlifting training routine. Pre- and post-test scores of the upper-quarter dynamic stability, strength, and function were measured for both groups using the shoulder active repositioning accuracy test, two-minute push-up test, and the upper-quarter Y-balance test (UQ-YBT) and one-arm hop test, respectively. Results: Post-test values were significantly greater for the normalized UQ-YBT test than pre-test values in both groups (p < 0.05). Post-test values of the experimental group were significantly greater than the control group (p < 0.05). Regarding the shoulder active repositioning accuracy test and the time of the one-arm hop test, post-test values were significantly lower than pre-test values for both groups (p < 0.05), and post-test values of the experimental group were significantly lower than those of the control group (p < 0.05). The post-test value of the two-minute push-up test of each group was significantly higher than the pre-test value (p < 0.05), without any significant difference between both groups (p > 0.05). Conclusions: Adding upper-body Biodex balance training to a regular weightlifting training routine was effective in enhancing the upper quarter′s dynamic stability and function.

Electromyographic analysis of the serratus anterior and upper trapezius in closed kinetic chain exercises performed on different unstable support surfaces: a systematic review and meta-analysis

Background

Multiple investigations have compared the electromyographic (EMG) activity of the scapular muscles between stable and unstable support surfaces during the execution of closed kinetic chain exercises. However, these comparative analyses have grouped different unstable surfaces (wobble board, BOSU, therapeutic ball, and suspension equipment) into a single data pool, without considering the possible differences in neuromuscular demand induced by each unstable support surface. This study aimed to analyze the individual effect of different unstable support surfaces compared to a stable support surface on scapular muscles EMG activity during the execution of closed kinetic chain exercises.

Methodology

A literature search was conducted of the Pubmed Central, ScienceDirect and SPORTDiscus databases. Studies which investigated scapular muscles EMG during push-ups and compared at least two support surfaces were included. The risk of bias of included articles was assessed using a standardized quality assessment form for descriptive, observational and EMG studies, and the certainty of the evidence was measured with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. A random-effects model was used to calculate effect sizes (ES, Hedge's g).

Results

Thirty studies were selected in the systematic review. Of these, twenty-three low-to-high quality studies (498 participants) were included in the meta-analysis. The main analyzes revealed, in decreasing order, greater UT EMG activity during push-ups performed on suspension equipment (ES = 2.92; p = 0.004), therapeutic ball (ES = 1.03; p < 0.001) and wobble board (ES = 0.33; p = 0.003); without effect on the BOSU ball. In addition, no effect was observed for SA on any unstable device. The certainty of the evidence ranged from low to very low due to the inclusion of descriptive studies, as well as high imprecision, inconsistency, and risk of publication bias.

Conclusion

These findings could be applied in scapular muscles strengthening in healthy individuals. The use of suspension equipment achieves higher UT activation levels. Conversely, the use of any type of unstable devices to increase the activation levels of the SA in shoulder musculoskeletal dysfunctions is not recommended. These conclusions should be interpreted with caution as the available evidence showed a low to very low certainty of evidence, downgraded mostly by inconsistency and imprecision.

Comparison of Activity in Scapular Stabilizing Muscles during Knee Push-Up Plus and Modified Vojta's 3-Point Support Exercises

Selective serratus anterior (SA) strengthening without compensatory movement of the shoulder stabilizers is essential for shoulder stability and functional movement without causing shoulder injury and dysfunction. The purpose of this study was to compare electromyographic (EMG) activity between the SA, upper trapezius (UT), lower trapezius (LT), and pectoralis major (PM) during the knee push-up plus (KPUP) and modified Vojta’s 3-point support (MV3PS) exercises. Scapular stabilizer muscle activity (UT, LT, SA, and PM) was investigated during the KPUP and MV3PS exercises in 40 healthy adults (19 males, 21 females) using surface EMG. Muscle activity of the SA was significantly higher during the MV3PS exercise than during the KPUP (p < 0.05). However, muscle activity in the PM was significantly lower during the MV3PS exercise (p < 0.05). In addition, the LT and UT showed less muscle activity during the MV3PS exercise, although the difference was not statistically significant (p > 0.05). These findings suggest that the MV3PS exercise better activates the SA than KPUP.

Optimal activation ratio of the scapular muscles in closed kinetic chain shoulder exercises: A systematic review

BACKGROUND

Muscle synergies contribute to scapular position during arm movement. The trapezius and serratus anterior (SA) muscles are the main stabilizers and are therefore the main target muscles of therapeutic exercises.

OBJECTIVE

To systematically review the current literature investigating the optimal activation ratio of the scapular muscles during a range of closed kinetic chain exercises.

METHODS

A systematic review search was conducted to identify studies reporting shoulder electromyography (EMG) activity during rehabilitation exercises in healthy participants. The search was conducted in PubMed, Cochrane Library, MEDLINE, CINAHL, Scopus, SPORTDiscus, and ScienceDirect. The included studies reported closed kinetic chain exercises and the muscle activity as a percentage of maximum voluntary isometric contraction (%MVIC) or muscle ratios of the lower trapezius (LT), middle trapezius (MT), and SA with respect to the upper trapezius (UT). Muscle ratios were classified as optimal if they were equal to or lower than 0.6, and the adapted Newcastle-Ottawa Scale (NOS) was used to evaluate the methodological quality of the selected studies.

RESULTS

Twenty-nine studies were included in this review; 7 main exercises and 30 variations of these were reported. The average electromyographic activity of the concentric and eccentric phase was considered. Half Push Up, Push Up Plus, and Scap Protraction exercises showed optimal SA activity (UT/SA < 0.6), while Press Up, Half Push Up, and One Hand Plank exercises showed optimal LT activity (UT/LT < 0.6). According to the NOS, 15 studies were classified as moderate methodological quality.

CONCLUSIONS

The exercises in higher positions (e.g. exercises with the trunk closest to the vertical line) or unstable surfaces tend to favor UT activity over the MT, LT and SA. The exercises including scapular retraction showed optimal UT/MT and UT/LT ratios, while those including scapular protraction showed optimal UT/SA ratios. This will assist therapists in the correct selection of exercises for shoulder rehabilitation.

Periscapular activity in subjects with scapular dyskinesis during push-ups on stable and unstable support surfaces

BACKGROUND: The scapular dyskinesis has been described as a sign of scapular instability due to weakness or imbalance of scapular muscles. OBJECTIVE: The aim of this study was to compare the EMG activity of the periscapular and abdominal muscles of asymptomatic subjects without and with scapular dyskinesis type II during a push-up exercise performed on different surface stability conditions. METHODS: Twenty-seven physically active men were allocated into two groups: the Control group (n= 14); and the Dyskinesis group (n= 13). All participants performed three variations of the push-up exercise: Stable, Push-up with hand instability, and Push-up with hand and feet instability. The EMG activity of serratus anterior, upper (UT), middle (MT) and lower (LT) trapezius, external oblique (EO) and rectus abdominis (RA) was recorded during each task. RESULTS: The control group showed an increase in MT activity (mean difference -3.46 to 8.66) under both instability conditions compared to stable push-ups (p< 0.001). The comparison between groups showed that the control group had higher MT activity (mean difference -10.07 to 13.82) compared to the dyskinesis group under unstable conditions (p< 0.012). CONCLUSION: The insertion of unstable surfaces increased MT activity in the control group only. The insertion of the unstable surface, either the hands or the footrest, did not provide significant effects for the other muscles.

Use of unstable exercises in periscapular muscle activity: A systematic review and meta-analysis of electromyographic studies

BACKGROUND

The use of unstable surfaces has been proposed to increase the neuromuscular demand. This strategy has been adopted to generate an increase in the activity of periscapular muscles due to its role in the stabilization of the scapula. However, the influence of this instability on the EMG activity remains uncertain. The aim of this study was to analyze the effects of using unstable surfaces on the EMG activity of the periscapular muscles.

METHODS

A comprehensive search in the PubMed, EMBASE, SCIELO, Web of Science, SCOPUS, Cochrane and LILACS databases was undertaken from their year of inception up to December 2019. Studies which directly investigated the EMG activity of periscapular muscles in healthy individuals while performing exercises for the upper limbs in stable and unstable conditions.

RESULTS

A total of 33 studies which evaluated a total of 678 healthy individuals were found according to the eligibility criteria. A meta-analysis identified that the EMG activity of the upper trapezius showed a trivial increase with the insertion of the unstable surface (P = 0.04; SMD = 0.14 [95%CI 0.00, 0.27]). No significant effects were observed on the middle trapezius (P = 0.10) and lower trapezius (P = 0.25). A decrease of the anterior serratus EMG activity with a small effect size was observed by implementing an unstable surface (P = 0.01; SMD = -0.21 [95%CI -0.36, -0.05]).

CONCLUSION

The use of unstable surfaces generated a trivial increase in the upper trapezius activity, and a slight decrease in the anterior serratus activity. No effect was observed on the middle and lower trapezius.

Effects of Kinesiology Taping on Shoulder Posture and Peak Torque in Junior Baseball Players with Rounded Shoulder Posture: A Pilot Study

Rounded shoulder posture (RSP) causes an imbalance of the adjacent joints due to the malalignment of the shoulder joint, and thus affects the strength of the muscles surrounding the shoulder. This study aimed to investigate the effect of rounded shoulder taping (RST) on shoulder posture and muscle strength in junior baseball players. Nineteen junior baseball players participated in the study, which used a crossover design at an interval of 1 week. The participants were randomized to receive rounded shoulder taping (RST) and sham kinesiology taping (SKT) using kinesiology tape. RSP was measured using two 12-inch combination squares, and shoulder peak torques were measured by isokinetic equipment. The results showed that RST led to significant changes in RSP (p < 0.05), but no significant changes were observed with SKT (p < 0.05). RST led to significant changes in the peak torques of external rotation and internal rotation of the shoulder (p < 0.05), but no significant changes were observed with SKT (p < 0.05). These results suggest that RST could help to correct RSP and improve peak torque of external and internal rotation of the shoulders of junior baseball players with RSP.

Effect of push-up variations performed with Swiss ball on muscle electromyographic amplitude in trained men: A cross-sectional study

PURPOSE

To compare the use of three variations of push-ups: traditional (stable surface), performed with hands on the Swiss ball (Swiss ball-hands), and performed with feet on the Swiss ball (Swiss ball-feet) on surface electromyography activity (sEMG) in the agonist and stabilizer muscles.

METHODS

Ten trained men (26 ± 5 years, 76.8 ± 8.7 kg, 1.70 ± 0.06 m) performed one experimental protocol within-subjects in a randomized design. Each subject performed one set of 10 of each of the push-up variations (5-min rest between sets). The sEMG activity was assessed for pectoralis major, triceps brachii, anterior deltoids, and rectus abdominis. One-way repeated-measures ANOVA (Bonferroni) compared push-up variations within-muscles (p < 0.05).

RESULTS

Pectoralis major sEMG was similar between exercises. Anterior deltoid sEMG activity was greater for stable surface than for Swiss ball-hands (p = 0.001). Triceps brachii sEMG activity was greater during Swiss ball-hands than during stable surface (p = 0.001) and Swiss ball-feet (p = 0.043), and Swiss ball-feet was greater than stable surface (p = 0.001). Rectus abdominis sEMG activity was greater during Swiss ball-hands than during stable surface (p = 0.0001) and Swiss ball-feet (p = 0.036), while Swiss ball-feet was greater than stable surface (p = 0.046).

CONCLUSIONS

Push-ups performed with hands on the Swiss ball may be considered an advanced variation that should be used when the goal is to achieve greater challenge of the rectus abdominis and triceps brachii. Novice subjects or those with weakness/injury should perform push-ups with hands on a stable surface, and with progression, push-ups with feet on Swiss ball could be adopted before hands on Swiss ball.

Serratus Anterior and Upper Trapezius Electromyographic Analysis of the Push-Up Plus Exercise: A Systematic Review and Meta-Analysis

CONTEXT

Whereas the serratus anterior (SA) and the upper trapezius (UT) work as a force couple for scapular motion, weakness of the SA and overactivation of the UT are often present in overhead athletes with shoulder dysfunction. Therefore, researchers addressing an intramuscular imbalance between the SA and UT have focused on finding exercises that target the weak SA and minimally activate the UT.

OBJECTIVE

To compare the effectiveness of push-up plus (PUP) exercise variants based on the electromyographic (EMG) activity of the SA and UT.

DATA SOURCES

A systematic search of PubMed and Scopus between January 1, 2000, and March 31, 2008.

STUDY SELECTION

Studies of PUP exercises that involved EMG analysis.

DATA EXTRACTION

We assessed study quality using the Critical Appraisal Skills Program. For the systematic analysis, the following data were extracted: (1) author, year, and study design; (2) participant characteristics; (3) type of PUP intervention; (4) EMG outcome measures; and (5) main results. For the meta-analysis, the EMG data of the SA and UT were calculated using the mean difference of EMG activity with a 95% confidence interval.

DATA SYNTHESIS

Based on 19 studies with 356 participants, different hand positions (the distance between the hands, shoulder-flexion angle, and elbow-flexion angle) and different lower extremity positions variably affected the activation of the SA and UT during the PUP exercise. Also, when participants performed the PUP on an unstable surface compared with a stable surface, UT activity increased 2.74% (95% confidence interval = 0.07%, 5.41%).

CONCLUSIONS

The standard PUP exercise elicited high EMG activity of the SA. Participants generated higher SA and lower UT EMG activity when they performed the PUP exercise on a stable surface in full elbow extension, with the hands placed shoulder-width apart, shoulder-flexion angles of 110° or 120°, and the ipsilateral lower extremity lifted.

Muscle Activity Patterns do not Differ Between Push-Up and Bench Press Exercises

Popular topics for upper-body resistance training involve the differences between hand positions, open versus closed chain exercises, and movement variations for the novice to the advanced. It was hypothesized that there will be no difference between closed (push-up) versus open (bench press) chain exercises for the primary muscle group activity nor would there be a difference between push-ups on the toes versus knees with respect to the percent contribution of each muscle. Surface muscle activity was measured for 8 upper-body and core muscles during a sequence of push-up and bench press variations with a normalized weight for 12 active men. Each participant completed push-ups and bench press exercises at each of 3 hand positions. The results demonstrated that there were few differences between closed versus open chain exercises for the primary muscle groups with the exception of core activation. In addition, in general, narrow hand positions yielded greater activation, and there were no significant differences between push-ups on the toes versus knees with respect to the percent contribution for the primary muscle groups. In conclusion, closed chain exercises may be preferred for functional training, and knee push-ups may be ideal as a novice push-up variation.

CLINICAL REASONING IN THE FACE OF UNCERTAINTY: CONSERVATIVE PHYSICAL THERAPY MANAGEMENT OF A TEENAGE ATHLETE DIAGNOSED WITH A PROXIMAL HUMERAL NON-OSSIFYING FIBROMA

BACKGROUND AND PURPOSE

There have been few published studies regarding the treatment of patients with non-ossifying fibromas (NOFs), either conservatively or operatively. The purpose of this case report is to discuss the clinical presentation and conservative management of a teenage athlete diagnosed with a proximal humerus NOF.

CASE DESCRIPTION

The subject was a 13-year-old male middle school student with a diagnosis of left shoulder pain over the prior year preventing him from participating in sports activities. The combination of radiological findings revealing a NOF and a thorough physical examination allowed for the development of a physical therapy plan of care to address impairments and functional limitations. The subject was seen for eight visits where a combination of manual therapy techniques, neural mobilizations, and therapeutic exercises were administered to the cervical and upper quarter regions. The subject's progress was tracked by measuring pain-free shoulder active range of motion (AROM) and monitoring changes using the Numerical Pain Rating Scale (NRPS) values throughout sessions.

OUTCOMES

After four sessions, AROM shoulder flexion and abduction increased from 123 º and 119 º to 160 º and 180 º respectively, and worst NRPS decreased from 9/10 to 3/10. Upon discharge after the eighth visit, the subject's DASH improved from 11.66 to 2.5. The subject remained pain free at an eight month follow up and returned to activity.

DISCUSSION

Thorough assessment of both neuromechanical sensitivity and musculoskeletal impairments may provide for the utilization of conservative treatment options for individuals with symptomatic NOFs.

LEVEL OF EVIDENCE

4.

Superior Training-Specific Adaptations With an 8-Week Yoak Push-up Training Program

Lima, C, Li, Y, Low, JL, Herat, N, and Behm, DG. Superior training-specific adaptations with an 8-week yoak push-up training program. J Strength Cond Res 32(9): 2409-2418, 2018-There are few progressive metastability training programs in the literature. The purpose of this study was to investigate changes in strength, endurance, muscle activation, and neuromuscular efficiency after an 8-week progressive, push-up training program under stable and unstable conditions. Nineteen male and female recreationally trained participants performed twice per week, an 8-week push-up training program, using either a relatively unstable suspension system (Yoak) or under stable conditions. Participants were tested in 2 separate sessions before and after training for chest press maximal voluntary isometric contraction (MVIC) forces, and unstable and stable push-up endurance. Participants were tested during all testing measures for anterior deltoid, biceps brachii (BB), triceps brachii (TB), and serratus anterior (SA) electromyography (EMG) activity. The training progression consisted of altering the suspension configurations, push-up height, and increasing the number of sets (1-3 sets). The stable group performed 153.3 and 33.8% less repetitions than the Yoak group when performing push-ups on the Yoak device or stable floor, respectively (p = 0.03). Training-induced MVIC forces were 9.2% (p = 0.03) greater for the Yoak vs. the stable group. Regarding neuromuscular efficiency, the Yoak group decreased (30.4%; p = 0.01) and stable group increased (97.8%; p = 0.02) antagonist BB EMG activity from pre- to post-training. Both groups decreased the TB fatigue index from pre- to post-training. Nevertheless, Yoak group demonstrated 12.5% (p = 0.09) and 8.9% (p = 0.02) lower fatigue indexes with TB and SA, respectively, than the stable group. These findings suggest that Yoak training demonstrates superior improvements over stable training for push-up endurance, neuromuscular efficiency, MVIC, and fatigue index.

EMG activity of the serratus anterior and trapezius muscles during the different phases of the push-up plus exercise on different support surfaces and different hand positions

[Purpose] The appropriate exercise prescription is crucial for achieving scapular stability and providing successful rehabilitation, and the Push-up Plus (PuP) exercise has an important role in shoulder rehabilitation. Consequently, this study examined the effect of support surface stability, hand positioning, and phase of exercise, on the trapezius and serratus anterior muscle contractions as well as on the EMG ratio of the upper/lower trapezius. [Subjects and Methods] Thirteen healthy male volunteers participated in this study. The subjects performed the PuP exercise on stable and unstable supporting surfaces with three different hand orientations. During the PuP exercise, the muscle activities of the upper (UT) and lower (LT) trapezius, as well as the serratus anterior (SA) were measured and expressed as percentages of maximum voluntary isometric contraction (%MVIC). [Results] The EMG activities of UT and LT were statistically greater during the push-up phase compared to the plus phase of the exercise. The contrary was recorded for the activity of the SA. SA was affected by the support surface as well as by the hand positioning. [Conclusion] The results suggest that different phases of the PuP exercise require different muscle stability actions with corresponding activations of appropriate muscle fibers. A detailed prescription of the required phase of the exercise can more effectively activate the scapula-thoracic musculature.

Effect of various hand position widths on scapular stabilizing muscles during the push-up plus exercise in healthy people

[Purpose] The purpose of this study was to determine the effect of various hand position widths during the push-up plus (PUP) exercise on the activity of the scapular stabilizing muscles and other upper-extremity muscles involved in the exercise. [Subjects and Methods] Nine healthy men participated in our study. The PUP exercise was performed on a stable surface in seven different hand positions, namely shoulder width (SW), and narrower SW (NSW) and wider SW (WSW) at 10%, 20%, and 30%. Surface electromyography was used to measure the muscle activities and muscle ratio of the upper trapezius (UT), middle trapezius, lower trapezius (LT), serratus anterior (SA), pectoralis major, deltoid anterior, latissimus dorsi (LD), and triceps muscles. [Results] The SA and LD muscle activities significantly decreased in the 30% NSW and 20% WSW hand positions, respectively. The UT/LT muscle ratio significantly increased in the 30% WSW hand position. [Conclusion] The results of this study suggest that during the PUP exercise, the SW hand position should be used. In the 30% NSW hand position, the SA muscle activity decreased, and the UT/ LT ratio increased in the 30% WSW hand position.

The sit up test to exhaustion as a test for muscular endurance evaluation

AIMS/HYPOTHESIS

The aim of this study was to examine the sit up test to exhaustion as a field test for muscular endurance evaluation in a sample of sedentary people of both sexes.

METHODS

A cross-sectional study was performed. Three-hundred-eighty-one participants volunteered for the study (28.5 ± 10.0 years; 168.2 ± 8.9 cm; 65.1 ± 11.1 kg), of which 194 males (27.5 ± 10.2 years; 173.6 ± 7.0 cm; 71.2 ± 5.2 kg) and 187 females (29.6 ± 10.1 years; 162.6 ± 7.1 cm; 58.7 ± 8.9 kg). Each subject voluntarily and randomly performed: a sit up test (SUT), a push up test (PUT), and a free weight squat test (ST), all till exhaustion. A multiple regression analysis was adopted for data analysis. Subsequently a percentile model for muscle endurance was developed. The 25th, 50th, and 75th percentile were identified as upper limit for low muscular endurance, average muscular endurance, and lower limit for high muscular endurance, respectively.

RESULTS

Considering the sit up test as the dependent variable, the coefficients (R(2) = 0.23; r = 0.49; p < 0.001), and (R(2) = 0.31; r = 0.57; p < 0.001) emerged from a multiple regression analysis applied with respect to the push up test and the squat test, respectively. Gender stratification showed regression coefficients of (R(2) = 0.19; r = 0.44; p < 0.001) for SUT vs. PUT, and (R(2) = 0.30; r = 0.56; p < 0.001) for SUT vs. ST in male; and (R(2) = 0.23; r = 0.49; p < 0.001) for SUT vs. PUT, and (R(2) = 0.34; r = 0.59; p < 0.001) for SUT vs. ST in female.

CONCLUSIONS/INTERPRETATION

The SUT showed low inter-relation with the other proposed tests indicating that the adoption of a single test for the global evaluation of muscle endurance is not the optimal approach. Moreover, the SUT was found to be inexpensive, safe, and appropriate for core muscle endurance measurement for both male and female.

Effect of Vibration Frequency on Serratus Anterior Muscle Activity during Performance of the Push-up Plus with a Redcord Sling

[Purpose] We investigated the effect of vibration at various frequencies on serratus anterior (SA) muscle activity. [Subjects] Ten male subjects were recruited. [Methods] The subjects performed the push-up plus exercise supported by straps above the surface and vertical ropes in the Redcord sling. During the push-up plus, vibrations of 0, 30, 50, or 90 Hz were applied to the Redcord sling using a mechanical vibration apparatus attached to the rope. SA muscle activity was recorded using electromyography. [Results] SA muscle activity at the 50 Hz vibration frequency was significantly higher than that of no vibration. [Conclusion] Performing the push-up plus using a Redcord sling with mechanical vibration of 50 Hz effectively increased SA muscle activity.