A Quasi-Randomized Clinical Trial to Compare the Effects of Suspension Versus Instability Training on Balance.

CONTEXT: Suspension training devices are becoming increasingly popular. Most studies analyzed the effectiveness according to diverse measures in patients with or without conditions at any age. The characteristics of suspension training are very specific and can increase instability and; therefore, enhance balance. The goal was to determine the effects of suspension training on balance by comparing it with instability training. DESIGN: Two-arm, randomized trial. METHODS: 44 young adults, aged 22.4 years old, with no musculoskeletal condition, took part. There were 2 interventions, suspension and instability training, designed with 12 sessions in 4 weeks. The primary outcome was the Y-Balance test. Other balance outcomes were the Emery and jumping sideways tests, and platform measures while standing. RESULTS: Suspension and instability training were effective in enhancing balance in terms of the primary outcome, the Y-Balance test, with no between-group differences. Instability training enhanced the Emery test over suspension training (P = .018), but the latter was more effective in the jumping sideways test (P = .003). Neither of the training improved static balance measures. CONCLUSIONS: Training with suspension devices is effective in enhancing dynamic balance, with similar improvements to instability training. Importantly, the magnitude of change and the frequency of responders to intervention in terms of motor coordination and keeping balance in unstable conditions appear to be sensitive to the type of training.

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.

Exploring of two different equated instability resistance training programs on measure of physical fitness and lower limb asymmetry in pre-pubertal weightlifters.

BACKGROUND: Although previous research in pediatric populations has reported performance enhancements following instability resistance training, the effects of different volumes on measures of balance, strength and power and lower limb asymmetry remain unclear. OBJECTIVE: To compare the effect of two 8-week instability resistance training programs (IRT1: 2 sets x 8 repetitions, 20% one-repetition maximum (1RM); IRT2: 2 sets x 4 repetitions, 40% 1RM) in balance (center of pressure displacements), 1RM, single-leg jumps, and inter-limb asymmetry of prepubescent weightlifters. METHODS: Thirty-two male athletes (10.94 ± 0.47 yrs, 17.05 ± 0.14 kg/m2, and 6.44 ± 0.93% bodyfat) voluntarily participated and combined IRT (front and back squat, lunge, and deadlift) with their usual weightlifting training. Nonparametric tests evaluated the differences between pre- and post-intervention. RESULTS: Significant improvements were encountered in all the variables for both groups (effect sizes [ES] from 0.46 to 2.60), except the inter-limb asymmetry and the velocity of displacement of the center of pressure, which did not improve in IRT2. It is also worth highlighting that in the single-leg jumps and center of pressure displacements, whereas no significant differences were observed between IRT1 and IRT2 in the baseline, significant differences appeared in the follow-up measurements. CONCLUSION: IRT combined with weight-lifting training improves prepubescent weightlifters' performance; therefore, strength and conditioning coaches may consider including unstable devices with low loads into an overall conditioning program and warm-ups for prepuberal male weightlifters to promote their physical fitness and potentially decrease inter-limb asymmetry. TRIAL REGISTRATION: This study does not report results related to healthcare interventions using human participants; therefore, it was not prospectively registered.

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.

Ajustes cinemáticos do complexo articular do tornozelo sobre diferentes superfícies instáveis / Kinematic adjustments of the ankle joint complex on different unstable surfaces

INTRODUÇÃO: Poucos estudos discutem as reações corporais de indivíduos saudáveis no momento em que os exercícios em superfícies instáveis estão sendo executados, embora os efeitos do treinamento ­ efeitos crônicos do exercício- sejam bastante estudados. OBJETIVO: Descrever a cinemática articular do tornozelo e retropé durante essa interação. MÉTODOS: Dezoito voluntários participaram do estudo. A posição articular da região do tornozelo foi estudada em três superfícies: Airex® Balance-pad, BOSU® e chão (controle). Para análise estatística, utilizou-se ANOVA e Pós-teste de Tuckey, considerando um nível de significância menor que 0,05. RESULTADOS: A posição articular da região tornozelo no plano sagital foi diferente no BOSU® em relação ao Airex® (p < 0.001) e ao chão (p < 0.001). O tornozelo ficou em posição mais próxima à neutra no AIREX® e no chão. Com o BOSU, a dorsiflexão foi acentuada. Não houve diferença da posição média no no plano frontal. A variabilidade da posição da região do tornozelo foi maior no BOSU® que no Airex® (p < 0.001) e no chão (p < 0.001), tanto no plano sagital, quanto no plano frontal. A frequência média de deslocamento da posição articular na região do tornozelo no plano sagital foi maior no BOSU® que no chão (p < 0.001); e no plano frontal, para o retropé, foi maior no BOSU® que no Airex® (p < 0.001) e chão (p < 0.001). CONCLUSÃO: Houve diferença no comportamento articular da região do tornozelo na condição BOSU® em relação às demais nas superfícies utilizadas, havendo um aumento das oscilações articulares no processo de controle postural em condições mais instáveis e maior dosiflexão no BOSU®. [AU]

INTRODUCTION: There are few studies approaching the bodily reactions of healthy individuals while performing exercises on unstable surfaces, although the training effects ­ exercise chronic effects - are well studied. OBJECTIVE: The goal of this study is to describe the ankle and rear foot region osteoarticular kinematic during this interaction. METHODS: Eighteen volunteers participated in the study. The ankle region osteoarticular displacement was studied in three different surfaces: AIREX® Balance-pad, BOSU® and Ground (control). Statistical analysis was performed using ANOVA and Tukey test, considering a significance level of 0.05. RESULTS: The position of the ankle joint in the sagittal plane was greater in the BOSU® than in the AIREX® (p < 0.001) and ground (p < 0.001). The ankle was close to the neutral position in the AIREX® and on the ground. With BOSU, the dorsiflexion was accentuated. Considering the frontal plane, there was no difference in the rear foot position. Moreover, the variability in the ankle region position in sagittal and frontal planes was higher in BOSU® than AIREX® (p < 0.001) and ground (p < 0.001). The mean frequency of the ankle position in the sagittal plane was greater in the BOSU® than on the ground (p < 0.001), and, in frontal plane, the rear foot frequency displacement was largest in the BOSU® than in the AIREX® (p < 0.001) and on the ground (p < 0.001). CONCLUSION: There were observed differences in ankle region postural control strategies in the BOSU® condition when compared with the other surfaces tested. The ankle and rear foot oscillations increase and there is a greater dorsiflexion for the postural control under the most unstable condition - BOSU. [AU]

Lower-extremity resistance training on unstable surfaces improves proxies of muscle strength, power and balance in healthy older adults: a randomised control trial.

BACKGROUND: It is well documented that both balance and resistance training have the potential to mitigate intrinsic fall risk factors in older adults. However, knowledge about the effects of simultaneously executed balance and resistance training (i.e., resistance training conducted on unstable surfaces [URT]) on lower-extremity muscle strength, power and balance in older adults is insufficient. The objective of the present study was to compare the effects of machine-based stable resistance training (M-SRT) and two types of URT, i.e., machine-based (M-URT) and free-weight URT (F-URT), on measures of lower-extremity muscle strength, power and balance in older adults. METHODS: Seventy-five healthy community-dwelling older adults aged 65-80 years, were assigned to three intervention groups: M-SRT, M-URT and F-URT. Over a period of ten weeks, all participants exercised two times per week with each session lasting ~60 min. Tests included assessment of leg muscle strength (e.g., maximal isometric leg extension strength), power (e.g., chair rise test) and balance (e.g., functional reach test), carried out before and after the training period. Furthermore, maximal training load of the squat-movement was assessed during the last training week. RESULTS: Maximal training load of the squat-movement was significantly lower in F-URT in comparison to M-SRT and M-URT. However, lower-extremity resistance training conducted on even and uneven surfaces meaningfully improved proxies of strength, power and balance in all groups. M-URT produced the greatest improvements in leg extension strength and F-URT in the chair rise test and functional reach test. CONCLUSION: Aside from two interaction effects, overall improvements in measures of lower-extremity muscle strength, power and balance were similar across training groups. Importantly, F-URT produced similar results with considerably lower training load as compared to M-SRT and M-URT. Concluding, F-URT seems an effective and safe alternative training program to mitigate intrinsic fall risk factors in older adults. TRIAL REGISTRATION: This trial has been registered with clinicaltrials.gov ( NCT02555033 ) on 09/18/2015.

Effects of instability versus traditional resistance training on strength, power and velocity in untrained men.

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key PointsSimilar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs.Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training.RPE emerged as a useful tool to monitor exercise intensity during instability strength training.

Comparison of the effects of an eight-week push-up program using stable versus unstable surfaces.

BACKGROUND AND PURPOSE: Recently, the trend among physical training and rehabilitation professionals is the use of resistance exercise on unstable equipment in order to increase the effort of the agonist and stabilizing muscles. It is unknown if performing exercises on unstable surfaces provides a greater training stimulus as compared to training on a stable training surface. Therefore, the purpose of this research was to compare the effect that push-up training on stable and unstable surfaces had on strength performance in healthy young men. METHODS: Thirty subjects with experience in resistance training participated in push-up training two days per week for eight weeks on one of three different surfaces: the floor (Tp), the T-Bow® (TBp) or the BOSU® (Bp). RESULTS: Strength, as measured by one repetition maximum (1-RM) and muscle endurance, as measured by number of pushups performed did not improve significantly (p>0.05) for any of the intervention groups. CONCLUSIONS: The addition of unstable surfaces in push-up training does not provide greater improvement in muscular strength and endurance than push up training performed on a stable surface in young men. LEVELS OF EVIDENCE: 3b.

The impact of using a Swiss ball to exercise the lumbo-abdominal muscles / 中华物理医学与康复杂志

Objective To explore any changes in surface electromyogram (sEMG) signals from the lumboabdominal muscles during exercise on stable and unstable surfaces. Methods sEMG signals from the lumbo-abdominal muscles of 33 healthy young persons [18 male and 12 female; average age (26.5 ± 4.3 ) years] were measured with the FlexComp Infiniti apparatus.Each subject performed 5 exercises on and off a Swiss ball:sit,bridge,bridge with both knees flexed,reverse bridge as well as press-up. Results ①In bridging there was a significant increase in the activation of the erector spinae during exercise on the ball compared with on the stable surface.②Bridging with both knees flexed gave a significant increase in activations of the erector spinae,the external obliques and the transverses abdominus/internal obliques during exercise on the unstable surface compared with the stable surface.③During reverse bridging there was a significant increase in activation of the erector spinae and rectus abdominus during exercise on the unstable surface compared with the stable surface.④During press-ups there was a significant increase in activation of the rectus abdominus,the external obliques and the transverses abdominus/internal obliques during exercise on the ball compared with the stable surface. Conclusion The unstable surface provides better training stimulus for the activation of the lumbo-abdominal muscles.