The effects of various stair-climbing exercises on functional mobility and trunk muscle activation in community-dwelling older adults: A pilot randomized controlled trial

BACKGROUND

Stair-climbing (SC) is an essential daily life skill, and stair-climbing exercise (SCE) serves as a valuable method for promoting physical activity in older adults. This study aimed to compare the impact of SCEs with heel contact (HC) and heel off (HO) during SC on functional mobility and trunk muscle (TM) activation amplitudes in community-dwelling older adults.

METHODS

In the pilot randomized controlled trial, participants were randomly allocated to either the HC group (n = 17; mean age 75.9 ± 6.3 years) or the HO group (n = 17; mean age 76.5 ± 4.6 years). The HC participants performed SCE with the heel of the ankle in contact with the ground, while the HO participants performed SCE with the heel of the ankle off the ground during SC. Both groups participated in progressive SCE for one hour per day, three days per week, over four consecutive weeks (totaling 12 sessions) at the community center. We measured timed stair-climbing (TSC), timed up and go (TUG), and electromyography (EMG) amplitudes of the TMs including rectus abdominis (RA), external oblique (EO), transverse abdominus and internal oblique abdominals (TrA-IO), and erector spinae (ES) during SC before and after the intervention.

RESULTS

Both groups showed a significant improvement in TSC and TUG after the intervention (P < .01, respectively), with no significant difference between the groups. There was no significant difference in the EMG activity of the TMs between the groups after the intervention. The amplitude of TMs significantly decreased after the intervention in both groups (P < .01, respectively).

CONCLUSION

Both SCE methods could improve balance and SC ability in older adults while reducing the recruitment of TMs during SC. Both SCE strategies are effective in improving functional mobility and promoting appropriate posture control during SC in older adults.

The Duration of Non-Local Muscle Fatigue Effects

Non-local muscle fatigue (NLMF) refers to a transient decline in the functioning of a non-exercised muscle following the fatigue of a different muscle group. Most studies examining NLMF conducted post-tests immediately after the fatiguing protocols, leaving the duration of these effects uncertain. The aim of this study was to investigate the duration of NLMF (1-, 3-, and 5-minutes). In this randomized crossover study, 17 recreationally trained participants (four females) were tested for the acute effects of unilateral knee extensor (KE) muscle fatigue on the contralateral homologous muscle strength, and activation. Each of the four sessions included testing at either 1-, 3-, or 5-minutes post-test, as well as a control condition for non-dominant KE peak force, instantaneous strength (force produced within the first 100-ms), and vastus lateralis and biceps femoris electromyography (EMG). The dominant KE fatigue intervention protocol involved two sets of 100-seconds maximal voluntary isometric contractions (MVIC) separated by 1-minute of rest. Non-dominant KE MVIC forces showed moderate and small magnitude reductions at 1-min (p < 0.0001, d = 0.72) and 3-min (p = 0.005, d = 0.30) post-test respectively. The KE MVIC instantaneous strength revealed large magnitude, significant reductions between 1-min (p = 0.021, d = 1.33), and 3-min (p = 0.041, d = 1.13) compared with the control. In addition, EMG data revealed large magnitude increases with the 1-minute versus control condition (p = 0.03, d = 1.10). In summary, impairments of the non-exercised leg were apparent up to 3-minutes post-exercise with no significant deficits at 5-minutes. Recovery duration plays a crucial role in the manifestation of NLMF.

The effect of a suspension training on physical fitness, lower extremity biomechanical factors, and occupational health in Navy personnel: a randomized controlled trial

Optimal physical fitness is essential for military personnel to effectively meet their rigorous physical demands. This study aimed to investigate the effectiveness of a suspension training program on physical fitness, biomechanical risk factors for lower extremity injury, mental health, and work-related factors in Navy personnel. A total of 50 young men participated in a randomized controlled trial. The participants were randomly assigned to two groups (n = 25): the intervention group and the control group. The intervention group performed an eight-week suspension training session three times per week, while the control group maintained their daily duties. The primary outcome was physical performance. The secondary outcomes were determined biomechanical risk factors for lower extremity injuries, mental health, and work-related factors. The data were analyzed using the analysis of covariance (ANCOVA). Compared with the control group, the intervention group showed significant improvements in physical performance, biomechanical risk for lower extremity injuries, and work-related factors from baseline to follow-up (p ≤ 0.05). However, there was no improvement in mental health. Based on these findings, suspension training positively impacted physical fitness, reduced injury risk, and enhanced the work-related factors of Navy personnel. This study provides new insights for various related experts and military coaches because it is an easy-to-use and feasible method with minimal facilities.

The effect of 12-week core strength training on dynamic balance, agility, and dribbling skill in adolescent basketball players

Purpose

The purpose of the study was to examine the impact of core strength training on the dynamic balance, agility, and dribbling ability of adolescent basketball players.

Methods

A randomized controlled between-subjects design was employed. Forty-four male adolescent basketball players (aged 14.41 ± 3.22 years) were randomly divided into two groups: the core strength training (CST) group and the conventional training (CT) group. The CST program included 1-h sessions, three times/week for 12 weeks. In contrast, the CT group provided a thorough physical training program that targeted general conditioning rather than focusing solely on core strength. Three measurements were used to evaluate performance in players: the Star Excursion Balance Test, the Illinois Agility Test, and the Dribbling Test conducted at T0 (week 0), T1 (week 6), and T2 (week 12), respectively.

Results

Compared to the CT group, the CST group showed a greater improvement (p < 0.05) in dynamic balance, particularly in the anterior, posteromedial, and posterolateral directions, with significant interaction effects (p < 0.05) observed in these measures. Additionally, Bonferroni post-hoc revealed that the CST group demonstrated notably better agility (p < 0.05) at T2; whereas, improvements in dribbling skills were significant (p < 0.05) within the CST group from T1 to T2, but not when compared to the CT group (p > 0.05).

Conclusion

The 12-week CST program significantly improved dynamic balance, agility, and dribbling skills in adolescent basketball players, demonstrating its potential as a valuable training component. Future research should explore CST's impact on other sport-specific elements and its applicability to female players.

The effect of core stability training on the balance ability of young male basketball players

Introduction: This study aimed to investigate the impact of a 10-week Core Stability Training (CST) compared to Traditional Strength Training (TST) on the balance abilities of adolescent male basketball players. Methods: Subjects (age: 15.70 ± 0.75, height: 178.4 ± 8.31, weight: 66.55 ± 8.34) were randomly assigned to either the Core Stability Training group or the Traditional Strength Training group. Three selected balance assessment indicators included the Single-leg Standing with Eyes Closed Test, Star Excursion Balance Test, and Core Four-Direction Endurance Test. Results: 1) The scores were significantly different in both groups before and after the Single-leg Standing with Eyes Closed Test; (p < 0.01, d = 1.692, d = 1.837); 2) In the Star Excursion Balance Test, the scores of the experimental group showed significant difference (p < 0.05) or highly significant difference (p < 0.01) with an average effect size of (d = 1.727) when the left or right foot supported in the other directions before and after the training. However, there was no significant difference in scores in the c direction when the left foot supported (p > 0.05, d = 0.954); 3) In the Core Four-Direction Endurance Test, there were no significant differences in scores for the control group before and after training (p > 0.05, d = 0.567), while the experimental group showed significant differences in scores before and after training (p < 0.05, d = 1.889). Discussion: Both CST and TST were effective in enhancing the balance abilities of adolescent basketball players. CST, in particular, demonstrated improvements in dynamic balance and agility across multiple planes. Basketball coaches are encouraged to consider incorporating CST training programs into their overall training plans for optimal balance enhancement.

The effect of gender, age and sports specialisation on isometric trunk strength in Greek high level young athletes

Aim of the study was to compare the isometric strength of flexors and extensors trunk muscles between male and female elite adolescent athletes of different age and training experience. Absolute and relative trunk muscle isometric peak extension (PTE) and flexion (PTF) torque, as well as flexion/extension (F/E) ratio were evaluated in 388 elite adolescent athletes 188 males (Age: 15.4±1.8 years, Body height: 175.5±11.2 cm, Body mass: 68.8±14.5 kg, BMI: 22.1±0.3 kg/m2) and 207 females (Age: 15.1±1.6 years, Body height: 166.8±7.8 cm, Body mass: 60.8±8.4 kg and BMI: 21.8±0.4 kg/m2). Participants were assigned into seven different groups according to their sport specialisation (oars-paddle, swimming, contact-combat, team, racket, winter and mixed other sports). Significant effect of age (η2: 0.077-0.112, p < 0.05), gender (η2: 0.020-0.077; p < 0.05) and sport category factors (η2: 0.057-0.154. p < 0.005) for absolute/relative PTE, PTF and F/E ratio was found. The highest values were observed in contact-combat and the lowest in mixed other sports groups. F/E ratio significantly differs between the age groups, especially in female athletes. The present data suggest that TMSs and F/E ratio are highly affected by age, gender and sports specialisation in high level trained adolescents.

Back Extensor Strength as a Potential Marker of Frailty Using Propensity Score Matching and Machine Learning

This study assessed the potential of back extensor strength as an alternative marker of frailty. A total of 560 farmers were included. Computed tomography scans measured fat and muscle mass volumes at the mid-L4 vertebral level. Back extensor strength was measured in a seated posture. Multivariate linear regression was used to analyze the associations between back extensor strength and trunk muscle/fat compositions. The participants were divided into two groups based on back extensor strength. Propensity score matching, multivariate logistic regression, and Extreme Gradient Boosting (XGBoost) were employed to evaluate the relationship between Fried's frailty criteria and back extensor strength. Back extensor strength exhibited positive associations with abdominal muscle volume (r = 1.12) as well as back muscle volume (r = 0.89) (p < 0.05). Back extensor strength was linked to more frail status, such as reduced grip strength, walking speed, and frequent self-reported exhaustion. Multivariate logistic regression indicated that back extensor strength was associated with higher frail status (OR = 0.990), and XGBoost analysis identified back extensor strength as the most important predictor (gain = 0.502) for frailty. The prediction models using grip strength produced similar results (OR = 0.869, gain = 0.482). These findings suggested the potential of back extensor strength as an alternative frailty marker.

Electromyographic and Stabilometric Analysis of the Static and Dynamic "Standing Bird Dog" Exercise

(1) Background: The "bird dog" exercise is considered one of the most effective therapeutic exercises for lumbopelvic rehabilitation and the prevention and treatment of low back pain. The "standing bird dog" (SBD) exercise, executed in a single-leg stance, constitutes a natural and challenging variation in the "bird dog"; nevertheless, this exercise has not yet been investigated. This study provides a stabilometric and electromyographic analysis of the SBD performed in static and dynamic conditions and in ipsilateral and contralateral variations; (2) Methods: A time-synchronized motion capture system, wireless electromyography sensors, and triaxial force platform were used to analyze the selected SBD exercises; (3) Results: In dynamic conditions, the gluteus maximum, multifidus, lumbar erector spinae, and gluteus medius reached a mean activation level higher than in the static condition, with peak activation levels of 80%, 60%, 55%, and a 45% maximum voluntary isometric contraction, respectively. In the static condition, balance control was more challenging in the mediolateral compared to the anteroposterior direction. In the dynamic condition, the balance challenge was higher in the anteroposterior direction and higher than the static condition in both directions; (4) Conclusions: The SBD was proved to be effective for strengthening the hip and lumbar extensor muscles and provided a powerful challenge to single-leg balance control in both mediolateral and anteroposterior directions.

How Does Instability Affect Bench Press Performance? Acute Effect Analysis with Different Loads in Trained and Untrained Populations

(I) The execution of different sports involves a significant number of throws, jumps, or direction changes, so the body must be as stable as possible while performing a specific action. However, there is no classification of unstable devices and their influence on performance variables. Furthermore, the effect on athletes’ experience using instability is unknown. (II) The aim of this study was to analyze the power and speed parameters in bench press with different loads and unstable executions: (1) stable (SB), (2) with asymmetric load (AB), (3) with unstable load (UB), (4) on fitball (FB) and (5) on a Bosu® (BB). A total of 30 male participants (15 trained and 15 untrained) were evaluated for mean propulsive speed (MPS), maximum speed (MS), and power (PW) with different types of external load: a low load (40% of 1RM), medium load (60% of 1RM), and high load (80% of 1RM) in each condition. Variables were measured with an inertial dynamometer. (III) The best data were evidenced with SB, followed by AB (3–12%), UB (4–11%), FB (7–19%), and BB (14–23%). There were no differences between groups and loads (p > 0.05) except in the case of MS with 60% 1RM, where trained participants obtained 4% better data (p < 0.05). (IV) Executions with implements and equipment such as fitball and Bosu® do not seem to be the most recommended when the objective is to improve power or execution speed. However, situations where the load is unstable (AB and UB) seem to be a good alternative to improve stabilization work without high performance. Furthermore, experience does not seem to be a determining factor.

The effects of core stabilization exercises on the neuromuscular function of athletes with ACL reconstruction

Athletes who have undergone anterior cruciate ligament reconstruction (ACLR) often exhibit persistently impaired kinematics and strength. Core stability training appears to be effective for reducing high-risk landing mechanics and preventing primary anterior cruciate ligament (ACL) injuries; however, there have been few attempts to examine their effects in athletes who have undergone ACLR. This study aimed to investigate the effect of eight weeks of simple core stability training on core endurance, hip strength, and knee kinematics in ACLR athletes. Twenty-six male athletes (20-30 years old) with a history of ACL surgery with hamstring tendon autograft were randomly divided into training (n = 13) and control groups (n = 13). The training group performed core stability exercises for eight weeks before starting their team training; the control group did not receive any intervention. Both groups continued their regular team schedule. The core endurance, hip muscle strength, and knee kinematics were assessed by the McGill test, a hand-held dynamometer, and video-taping, respectively. Analysis of covariance test was used for data analysis. The training group showed a significant increase in core endurance, hip abductor and external rotator strength, knee flexion angle, and a significant decrease in the knee valgus angle during single-leg landing in post-training tests compared to their baseline tests (P < 0.05). Our results demonstrated that core stability exercise alters neuromuscular function to a level that is clinically acceptable and statistically significant. Because of the high incidence rate of secondary ACL injury after ACLR, it is recommended that athletes with a history of ACLR benefit from adding core stability exercises to warm-up routines or tertiary prevention programs even after completing post-operative rehabilitation. It is fast and not time-consuming to perform for athletes to reduce the risk factors of re-injury. Trial registration: This study was registered in the Iranian Registry of Clinical Trials with the number IRCT20190224042827N2, registered on 19 December 2019.

The effects of online pilates and face-to-face pilates in healthy individuals during the COVID-19 pandemic: a randomized controlled study

BACKGROUND

Along with the covid-19 process, people started to turn to online exercise methods. One of these methods is the pilates method, which increases the endurance of the core muscles. This study aims to analyze and compare the effects of online and face-to-face pilates methods.

METHODS

Fifty-eight healthy individuals aged 25-40 years were included in the study. Individuals were randomly divided into three groups; online pilates group (OPG), face-to-face pilates group (FPG), and control group (CG). Pilates groups were given pilates exercises in groups of three or four for eight weeks, three days a week, for 1 h a day, by the physiotherapist. The control group did breathing and relaxation exercises at home. Core muscular endurance, depression, and quality of life were assessed before and after eight weeks of training.

RESULTS

Core muscle endurance, depression, and quality of life improved after pilates in online and face-to-face pilates groups (p < 0.05). No change was found in the control group (p > 0.05). When the gains in the Pilates groups were compared, it was seen that the improvement in the Modified Biering-Sorensen test was more significant in the face-to-face pilates group, and the improvement in the trunk flexion test was more significant in the online group (p < 0.05), while the gains in other parameters were similar (p > 0.05).

CONCLUSIONS

As a result, healthy individuals have seen similar benefits in online and face-to-face pilates. Both methods are significant for gaining healthy habits and increasing physical activity in healthy individuals. Trial registration Retrospectively registered. NCT05309486, Registration date: 04/04/2022. URL: https://www.

CLINICALTRIALS

gov/ct2/show/NCT05309486?term=BULGUROGLU&draw=2&rank=1.

Superimposed vibration on suspended push-ups

Background

Superimposition of vibration has been proposed in sports training using several devices and methods to enhance muscle activation and strength adaptations. Due to the popularity of suspension training, vibration systems have recently been developed to increase the effects of this training method. The present cross-sectional study aims to examine the effects of superimposing vibration on one of the most popular exercises in strength and conditioning programs: push-ups.

Methods

Twenty-eight physically active men and women executed push-ups in three suspended conditions (non-vibration, vibration at 25 Hz, and vibration at 40 Hz). OMNI-Res scale was registered, and surface electromyographic signals were measured for the activity of the right and left external oblique, anterior deltoid, triceps brachii, sternal, and clavicular heads of the pectoralis major.

Results

A linear mixed model indicated a significant fixed effect for vibration at 25 Hz and 40 Hz on muscle activity. Suspended push-ups with superimposed vibration (25 Hz and 40 Hz) showed a significant higher activity on left (25 Hz: p = 0.036, d = 0.34; 40 Hz: p = 0.003, d = 0.48) and right external oblique (25 Hz: p = 0.004, d = 0.36; 40 Hz: p = 0.000, d = 0.59), anterior deltoid (25 Hz: p = 0.032, d = 0.44; 40 Hz: p = 0.003, d = 0.64), and global activity (25 Hz: p = 0.000, d = 0.55; 40 Hz: p = 0.000, d = 0.83) compared to non-vibration condition. Moreover, OMNI-Res significant differences were found at 25 Hz (6.04 ± 0.32, p = 0.000 d = 4.03 CI = 3.27, 4.79) and 40 Hz (6.21 ± 0.36 p = 0.00 d = 4.29 CI = 3.49, 5.08) compared to the non-vibration condition (4.75 ± 0.32).

Conclusion

Superimposing vibration is a feasible strategy to enhance the muscle activity of suspended push-ups.

Effects of a 6 week core strengthening training on measures of physical and athletic performance in adolescent male sub-elite handball players

The objective was to investigate the effects of a 6-week core strengthening training within the regular handball training sessions compared to regular handball training only. Male sub-elite handball players were randomly assigned to an intervention (INT: n = 13; age: 16.9 ± 0.6 years) or a control (CON: n = 13; age: 17.2 ± 0.8 years) group. The INT group performed the "big 3" core exercises cross curls-up, side bridge (both sides), and the quadrupedal stance ("birddog exercise") triweekly for 20-30 min while the CON group conducted regular handball training only. Pre- and post-training assessments included measures of muscular endurance (Closed Kinetic Chain Upper Extremity Stability Test [CKCUEST] and the Bourban test), shoulder mobility/stability (Upper Quarter Y Balance [YBT-UQ] test), and throwing velocity. The ANCOVA revealed significant differences between means in favour of the INT group for the dorsal chain (p < 0.001,η p 2 = 0.46) and the lateral chain (left side: p = 0.015,η p 2 = 0.22; right side: p = 0.039,η p 2 = 0.17) of the Bourban test, the composite score (p = 0.024,η p 2 = 0.20) of the throwing arm reach and the inferolateral reach direction (p = 0.038,η p 2 = 0.17), and the composite score (p = 0.027,η p 2 = 0.19) of the non-throwing arm reach of the YBT-UQ. However, performance in the CKCUEST and throwing velocity did not show any group-specific changes. Therefore, 6 weeks of core strengthening training were effective in improving some components of physical but no handball-specific athletic (i.e., throwing velocity) performance in adolescent male sub-elite handball players. Practitioners may still opt for this training regimen when stimulus variability is sought or when a low load/low movement approach (e.g., during rehabilitation) is favoured.

Assessment of the Speed and Power of Push-Ups Performed on Surfaces with Different Degrees of Instability

(I) Training in unstable conditions, with different elements, platforms, or situations, has been used because there is a significant increase in muscle activation, balance, proprioception, and even sports performance. However, it is not known how the devices used are classified according to performance variables, nor the differences according to instability experience. (II) This study aims to analyze the differences in power and speed in push-ups with different situations of instability in trained and untrained male subjects. Power and speed in push-up exercise were analyzed in 26 untrained and 25 trained participants in 6 different situations (one stable and five unstable) (1) stable (PS), (2) monopodal (PM), (3) rings (PR), (4) TRX^® (PT), (5) hands-on Bosu^® (PH) (6) feet on Bosu^® (PF). The variables were analyzed using a linear position transducer. (III) The best data were evidenced with PS, followed by PR, PM, PT, PH and PF. The trained subjects obtained better results in all the conditions analyzed in mean and maximum power and speed values (p < 0.001). The decrease in these variables was significantly greater in the untrained subjects than in the trained subjects in the PR situation (8% and 18% respectively). In PF there were differences between groups (p < 0.001), reaching between 32-46% in all variables. The difference between the two groups was notable, varying between 12-58%. (IV) The results showed a negative and progressive influence of instability on power and speed in push-ups. This suggests that instability should be adapted to the subject's experience and is not advisable in untrained subjects who wish to improve power.

Effect of the Trunk and Upper Limb Passive Stabilization on Hand Movements and Grip Strength Following Various Types of Strokes—An Observational Cohort Study

Almost half of the patients surveyed report impaired function of the upper limbx and handx after stroke. The effect of the passive trunk and shoulder stabilization on the recovery of coordinated hand movement is unclear. This study examined whether passive stabilization of the trunk and shoulder could improve the functional state of the hands after various types of strokes. It is an observational prospective cohort study conducted at the Rehabilitation Clinic in two parallel groups of patients with four different types of strokes (hemorrhagic and ischemic of the brain, similar to the cerebellum). A total of 120 patients were analyzed. Patients were examined in various positions: sitting without a backrest with the upper limb adjacent to the body, supine with the upper limb perpendicular to the body, and supine with the arm stabilized in relation to the patient’s body. Hand Tutor devices and a hand dynamometer were used for the measurements. The frequency and maximum range of motion as well as the grip strength were measured in three different positions of the trunk and upper limb. Passive stabilization of the trunk and shoulder showed more statistically significant differences in Group II. In group II, both in patients after hemorrhagic stroke (wrist Hz p = 0.019; wrist ROM p = 0.005; Hz F5 p = 0.021; Hz F4 p = 0.016; Hz F3 p = 0.019; Hz F2 p = 0.021) and ischemic stroke (p = 0.001 for wrist Hz, wrist ROM, Hz F from 5 to F2; and ROM F1; ROM F3 p = 0.009; ROM F2 p = 0.010), and hemorrhagic cerebellum, improvement of parameters was observed. Stabilization of the upper limb and passive stabilization of the trunk improved the frequency and range of movements in the radiocarpal joint and in the fingers of patients after stroke, regardless of the type of stroke.

A comparison of muscle activation and concomitant intermuscular coupling of antagonist muscles among bench presses with different instability degrees in untrained men

The aim of this study was to analyze and compare the muscle activation and concomitant intermuscular coupling of antagonist muscles among bench presses with different instability degrees. Twenty-nine untrained male college students performed bench press exercises at an intensity of 60% 1 RM on three conditions: small unstable bench press with Smith machine (SBP), medium unstable bench press of free weight (FWBP), and large unstable bench press with increased instability by suspending the load with elastic bands (IIBP). One-way repeated measures analysis of variance was used to compare integrated EMG activity values of the biceps brachii (BB), posterior deltoid (PD), long head of the triceps brachii (TB), anterior deltoid (AD), upper portion of the pectoralis major (PM) muscles, and phase synchronization index (PSI) of BB-TB and PD-AD antagonist muscle pairs. A higher integrated EMG of BB muscle was found during bench press with a more unstable condition. IIBP showed a higher integrated EMG of prime movers (TB, AD, and PM) and stabilizing of BB than SBP and FWBP. PSI between muscle pairs of BB-TB in the gamma frequency band was higher in SBP than the other bench presses with unstable conditions, which may be related to the optimal “internal model” for antagonist muscles during bench press exercise. Therefore, IIBP training may be an effective accessory exercise to maintain a higher level of muscle activation across primary and stabilizing muscles with a lighter load for untrained men, while SBP may be a suitable bench press exercise for untrained participants who have not developed the neuromuscular adaptations necessary for correct stabilization of the elbow joint.

Effects of Eight-Week Circuit Training with Core Exercises on Performance in Adult Male Soccer Players

Core exercises have been widely promoted in the last 25 years. However, the scientific debate about its efficacy for improving individual and team sports performance is still open. Thus, the present study aims to investigate the effects of circuit training with a core exercise program on physical performance in competitive amateur soccer players. The training was conducted during the off-season period, two times per week for 8 weeks. Pre- and post-evaluations were conducted using the following tests: Y-Balance Test (YB), standing long jump (SLJ), medicine ball chest press (MBC), curl-up (CU), and Illinois Agility Test (IAT). A total of 19 adults were divided into an experimental group (EG, n = 11, age 22 years, weight 71.2 ± 4.8 kg, height 174 ± 5.8 cm) and a control group (CG, n = 8, age 22 years, weight 73.2 ± 4.1 Kg, height 176 ± 6.3 cm). The EG showed significant improvements in lower and upper body strength, core endurance and balance, whereas the CG did not report significant changes in the pre- and post-test comparison. Despite study limitations, our positive results show that circuit training with core exercises appears to be a good strategy for performance improvement in adult soccer players.

Effects of core training on dynamic balance stability: A systematic review and meta-analysis

Core stability has a strong relationship with dynamic balance stability (DBS). The purpose of this review with meta-analysis was to analyse the effects of core training programmes from different studies on DBS. A literature search was performed using different databases. Subgroups analyses on duration, training frequency, total sessions, chronological age, training status, equipment and movements were performed. A random-effects model for meta-analyses was used. Thirteen studies were selected for the systematic review and 10 for the meta-analysis, comprising 226 participants. A moderate effect was noted for core training on DBS (p < 0.001; ES = 0.634). Greater DBS improvements were found in core training interventions with ≤6 weeks (ES = 0.714), after high volume (ES = 0.787) and more frequent interventions (ES = 0.787), as well as in younger participants (ES = 0.832). In addition, body weight exercises may be better than med ball, swiss ball or band resisted exercises. Core training improves DBS among athletes and a non-trained population, creating a more solid stable base that allows better lower extremity movements. This could be more effective considering different modulators ≤6 weeks intervention, >2 sessions per week, >17 total sessions, body weight core programmes and applied to ≤18.0 years old.

The Influence of Maturity Status on Dynamic Balance Following 6 Weeks of Eccentric Hamstring Training in Youth Male Handball Players

Information about when to apply an appropriate eccentric hamstring strength training stimulus during long-term athlete development is essential for effective programming and improving balance performance. This study examined the effects of six-week eccentric hamstring training on dynamic balance performance in youth handball players of different maturity statuses (pre- or post-peak height velocity (PHV)). A randomized controlled design with 45 young male handball players (14.6 ± 0.3 years) from a local national handball club were randomly allocated to a 6 week, twice weekly eccentric hamstring training in two experimental groups: a pre-PHV (maturation offset: −2.13 ± 0.63, n = 10) and post-PHV (maturation offset: 0.79 ± 0.34, n = 12) group and two control groups: maturation offset: −2.09 ± 0.61, n = 10 and maturation offset: 0.55 ± 0.67, n = 13. Dynamic balance performance was evaluated by using the composite score during the lower quarter Y-balance test from pre- and post-intervention. A significant effect on balance scores was found from pre to post (F = 11.4; p = 0.002; η2p = 0.22), intervention (F = 5.4; p = 0.025; η2p = 0.12), and maturation (F = 369; p < 0.001; η2p = 0.9), but no significant interaction effects were found (F ≥ 3.3; p ≥ 0.077; η2p ≤ 0.07). Post hoc analysis revealed that the post-PHV group had a higher score than the pre-PHV group. Furthermore, that dynamic balance increased in the post-PHV group after intervention much more in the control post-PHV group. It was concluded that somatic maturation influences dynamic balance performance and that eccentric hamstring training results in greater improvement in balance performance in young male handball players for the post-pubertal group.

The effectiveness of injury prevention programs that include core stability exercises in reducing the incidence of knee injury among soccer players: A systematic review and meta-analysis

BACKGROUND: The knee is one of the most common sites of injuries among soccer players. The incidence of knee injuries can be reduced by improving the neuromuscular control and core stability. OBJECTIVE: This study aimed to evaluate the effectiveness of injury prevention programs that include core stability exercises in reducing the incidence of knee injuries among soccer players. METHODS: Data were obtained from different databases (1985–2021). Only randomized controlled trials that used injury prevention programs that include core stability exercise to prevent knee injuries were included. The keywords used during the search were ‘knee injuries’, ‘core stability exercises’, ‘FIFA 11+’, ‘prevention of knee injuries’, ‘anterior cruciate ligament injury’ and variations of these search terms. RESULTS: The pooled results of 7828 soccer players and 863700 exposure h showed an overall injury reduction of 56% per 1000 h of exposure in the intervention group compared to the control group with an injury risk ratio of 0.44 (95% CI 0.321–0.619; P= 0.001). CONCLUSIONS: Injury prevention programs that include core stability exercises reduce knee injury rates among soccer players by 56% (46% in male and 65% in female soccer players).

Strength and Power-Related Measures in Assessing Core Muscle Performance in Sport and Rehabilitation

While force-velocity-power characteristics of resistance exercises, such as bench presses and squats, have been well documented, little attention has been paid to load, force, and power-velocity relationships in exercises engaging core muscles. Given that power produced during lifting tasks or trunk rotations plays an important role in most sport-specific and daily life activities, its measurement should represent an important part of the test battery in both athletes and the general population. The aim of this scoping review was 1) to map the literature related to testing methods assessing core muscle strength and stability in sport and rehabilitation, chiefly studies with particular focus on force-velocity-power characteristics of exercises involving the use of core muscles, 2) and to identify gaps in existing studies and suggest further research in this field. The literature search was conducted on Cochrane Library databases, Scopus, Web of Science, PubMed and MEDLINE, which was completed by SpringerLink, Google Scholar and Elsevier. The inclusion criteria were met in 37 articles. Results revealed that among a variety of studies investigating the core stability and core strength in sport and rehabilitation, only few of them analyzed force-velocity-power characteristics of exercises involving the use of core muscles. Most of them evaluated maximal isometric strength of the core and its endurance. However, there are some studies that assessed muscle power during lifting tasks at different loads performed either with free weights or using the Smith machine. Similarly, power and velocity were assessed during trunk rotations performed with different weights when standing or sitting. Nevertheless, there is still scant research investigating the power-velocity and force-velocity relationship during exercises engaging core muscles in able-bodied and para athletes with different demands on stability and strength of the core. Therefore, more research is needed to address this gap in the literature and aim research at assessing strength and power-related measures within cross-sectional and intervention studies. A better understanding of the power-force-velocity profiles during exercises with high demands on the core musculature has implications for designing sport training and rehabilitation programs for enhancement of athletes' performance and/or decrease their risk of back pain.

Assessment of the Impact of the Tipstim® Device Application and the Study Position on Motor Coordination and Grip Strength of the Affected Upper Limb Post-Ischemic Stroke—A Randomized Parallel Crossover Trial

In the acute phase of stroke, most patients have reduced efficiency of the upper limb and in the chronic phase more than half of these patients still have a deficit in the mobility of the upper limb. The aim of this study was to investigate the effect of using the tipstim® device and the tested position of the body and affected upper limb on parameters of motor coordination and grip strength in patients after an ischemic stroke. A randomized, parallel crossover study was conducted in the Rehabilitation Department. The study included 29 people aged 68 ± 9.2 years, 5–7 weeks after ischemic stroke. Patients were randomly assigned to two parallel groups (A/B = 15 people and B/A = 14 people). In each of them, the patient received both experimental (A = tipstim®) and control (B = placebo effect) treatment in a specific order. The HandTutor was used to measure the parameters of motor coordination (maximum range of motion and frequency of motion). We also used an electronic dynamometer to measure the handgrip strength. The patients were examined in two positions: sitting (unstable) and lying with the trunk and affected upper limb stabilized. Results: The analysis showed smaller differences between the measurements in the A/B group than in the B/A group, both without stabilization and with stabilization (wrist Hz = p ˂ 0.001; fingers 2–5 Hz = p ˂ 0.001; handgrip strength = p ˂ 0.049 and p ˂ 0.003). When comparing the influence of the tested position on the results of motor coordination and the handgrip strength, statistically significant differences were found in the placebo group in a stable position (Hz wrist p = 0.007, MaxROM wrist = 0.038, HzF5 = 0.039, MaxROM F4 = 0.035, HzF3 = 0.035, MaxROM F3 = 0.010, HzF2 = 0.049). Conclusions: Repeated use of the tipstim® device did not improve the tested parameters. A significant improvement in the results of coordination of movements and grip strength is possible in a stable position, lying down.

Core Muscle Activation With Foam Rolling and Static Planks

The objective of this study was to compare the activation of the core (trunk) musculature during quadriceps and hamstrings foam rolling (FR) vs. prone and supine/reverse static planks to determine if FR is a viable means of training the core musculature. Using a randomized allocation, nine recreationally trained, young adults (18-26 years) performed two sets each of quadriceps and hamstrings FR as well as supine/reverse and prone static planks for 30-s each with 1-min rest between sets and 5-min rest between exercises. Electromyographic (EMG) activity of the lower abdominals (LA), external obliques (EO), lumbosacral erector spinae (LSES), upper lumbar erector spinae (ULES) muscle groups were normalized to a maximum voluntary contraction and analyzed. Quadriceps FR exhibited a very large magnitude greater LA activity compared to reverse plank (p = 0.033, d = 4.42) and hamstrings FR (p = 0.020, d = 3.49), respectively. The prone plank demonstrated very large magnitude higher EO EMG activity compared to reverse plank (p = 0.001, d = 9.17), hamstrings FR (p = 0.002, d = 8.14), and quadriceps FR (p = 0.011, d = 5.97). Reverse plank (p = 0.003, d = 12.06), and quadriceps FR (p = 0.002, d = 7.84) induced greater ULES activity compared to the prone plank and hamstrings FR, respectively. Reverse plank also exhibited very large magnitude higher LSES activity compared to the prone plank (p < 0.001, d = 7.68), hamstrings FR (p = 0.002, d = 4.11), and quadriceps FR (p = 0.005, d = 2.34), respectively. In conclusion, whereas reverse plank was the most effective activator of dorsal core muscles, quadriceps FR may also be a time efficient alternative exercise to activate back (ventral core) muscles. The prone plank is effective for ventral core muscles activation.

Motor Coordination and Grip Strength of the Dominant and Non-Dominant Affected Upper Limb Depending on the Body Position—An Observational Study of Patients after Ischemic Stroke

Stroke is one of the leading causes of human disability globally. Motor function deficits resulting from a stroke affect the entire body, but relatively often it is the upper limbs that remain ineffective, which is very limiting in everyday life activities. The finding in neurorehabilitation that trunk control contributes to upper limb function is relatively common but has not been confirmed in clinical trials. This observational prospective study aims to analyze the effect of the position of the trunk and the affected upper limb on the coordination and grip strength of the affected dominant and non-dominant hand and wrist in people after ischemic stroke. The research was carried out at the Department of Neurological Rehabilitation, on a group of 60 patients with acute ischemic stroke. A Hand Tutor device and a hand dynamometer were used for the main measurements of the motor coordination parameters (maximum range of motion, frequency of movement) and the grip strength of the dominant and non-dominant upper limb. The patients were examined in two positions: sitting without back support and lying on the back with stabilization of the upper limb. Higher and relevant results were observed in the non-dominant hand, in the supine position in terms of motor coordination parameters of the fingers (p = 0.019; p = 0.011) and wrist (p = 0.033), and grip strength (p = 0.017). Conclusions: The laying position and stabilization of the affected upper limb in the acute phase following ischemic stroke is more beneficial for the coordination of movements and grip strength of the non-dominant hand.

Importance of core stability for coordinated movement of the human body in stroke rehabilitation

OBJECTIVES

To examine the effect of core stability on parameters of coordinated movement of the trunk and lower extremities in post-stroke rehabilitation.

METHODS

A total of 55 subjects (mean age, 58 years) were included in the study: 33 patients after stroke (17 with ischemic cerebral stroke and 16 with cerebellar) and 22 neurologically healthy subjects with lower back pain. Participation was voluntary. All subjects were asked to complete two exercises: a dynamic movement in the seated position (leaning forward and back) and a march-in-place exercise with a high elevation of the knees. The two exercises were performed with and without contraction of the abdominal muscles. The frontal and sagittal inclination of the trunk during movement, gait speed, elevation of the feet, and muscle tension was recorded. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT04886466.

RESULTS

Core stability (abdominal contraction) was associated with more precise trunk movement in the frontal and sagittal plane, as well as higher elevation of the feet and a faster gait. This occurred in both post-stroke patients and neurologically healthy subjects with lower back pain.

DISCUSSION

Muscle tensions were generally lower in post-stroke patients compared to those with lower back pain syndrome but active abdominal tension muscles caused the increase of core stability and alter the trunk movement path, and improves gait and range of movement. Core stability training during stroke rehabilitation may help patients to achieve a higher level of coordinated movement.

A 10-Week Program of Combined Hippotherapy and Scroth's Exercises Improves Balance and Postural Asymmetries in Adolescence Idiopathic Scoliosis: A Randomized Controlled Study

Introduction: The most frequent type of spine abnormality throughout adolescence was adolescent idiopathic scoliosis (AIS). Hippotherapy improved posture, balance and gait of different musculoskeletal conditions. Therefore, this study aims to see how hippotherapy combined with Schroth exercises affected postural asymmetry and dynamic balance in AIS compared to traditional physiotherapy (Schroth exercises) alone. Materials and methods: In this randomized controlled trial, fifty-two patients with AIS (10–18 years, 37 girls and 15 boys) participated. They were arbitrarily allocated into two groups: experimental (19 female/8 male; aged 14.74 ± 1.79 years; Cobb angle 18.59 ± 2.66 degrees) and control (18 female/7 male; aged 15.04 ± 1.81 years; Cobb angle 19.32 ± 2.69 degrees) groups. Both groups received Schroth exercises for 10 weeks, three days/week. The experimental group additionally received hippotherapy training. Pre-treatment and post-treatment assessment for the scoliotic, kyphotic angle, pelvic obliquity, pelvic torsion and vertical spinal rotation and the anteroposterior, mediolateral and overall stability indices were assessed using the formetric system 4D and Biodex Balance System, respectively. Results: After intervention, both groups illustrated significant improvements in all examined variables (p < 0.05). The experimental group illustrated significant improvements in scoliotic angle, kyphotic angle, pelvic obliquity, pelvic torsion and vertical spinal rotation and the stability indices compared to the control group (p < 0.05). Conclusion: In adolescence idiopathic scoliosis, hippotherapy training combined with Schroth exercises improves posture asymmetry and balancing ability more effectively than Schroth exercises alone.

An online pilates exercise program is effective on proprioception and core muscle endurance in a randomized controlled trial

BACKGROUND

Proprioception is important for stability of body segments, postural control, and functionality. However, there are no studies in literature showing effects of online Pilates exercises that create proprioceptive inputs on vertebra on trunk proprioception.

AIMS

This study aims to reveal effect of online Pilates exercises conducted on trunk proprioception and core muscle endurance in healthy individuals.

METHODS

We included thirty-three healthy individuals between ages of 18 and 25 in study. Individuals were randomly divided into two groups. There were 17 individuals in Pilates group (PG), and 16 individuals in control group (CG). The PG was given online Pilates exercises by the physiotherapist in groups 3 days a week for 6 weeks, 1 h a day. There was no exercise program recommended for individuals in CG. We evaluated trunk proprioception with an inclinometer, core muscle endurance with three core endurance tests created by McGill, and prone bridge tests. All evaluations completed just before start of study and 2 days after 6-week training.

RESULTS

Two groups had similar demographic characteristics, and there was no difference between baseline measurements (p > 0.05). While improvement observed in PG in trunk proprioception and all of core muscle endurance tests (p < 0.05), no statistically significant difference reported in CG (p > 0.05).

CONCLUSIONS

We revealed that online Pilates exercises performed at mat level for 6 weeks in healthy individuals had positive effects on trunk proprioception and core muscle endurance with this study. Contribution of Pilates exercises to development of both muscular endurance and proprioceptive senses, even if performed at a distance, is important.

Influence of the Passive Stabilization of the Trunk and Upper Limb on Selected Parameters of the Hand Motor Coordination, Grip Strength and Muscle Tension, in Post-Stroke Patients

Objective: Assessment of the influence of a stable trunk and the affected upper limb (dominant or non-dominant) on the parameters of the wrist and hand motor coordination, grip strength and muscle tension in patients in the subacute post-stroke stage compared to healthy subjects. Design: An observational study. Setting: Stroke Rehabilitation Department. Subjects: Thirty-four subjects after ischemic cerebral stroke and control group-32 subjects without neurological deficits, age and body mass/ height matched were included. Main measures: The tone of the multifidus, transverse abdominal and supraspinatus muscles were assessed by Luna EMG device. A HandTutor device were used to measure motor coordination parameters (e.g., range of movement, frequency of movement), and a manual dynamometer for measuring the strength of a hand grip. Subjects were examined in two positions: sitting without back support (non-stabilized) and lying with stabilization of the trunk and the upper limb. Results: Passive stabilization of the trunk and the upper extremity caused a significant improvement in motor coordination of the fingers (p ˂ 0.001) and the wrist (p < 0.001) in patients after stroke. Improved motor coordination of the upper extremity was associated with an increased tone of the supraspinatus muscle. Conclusions: Passive stabilization of the trunk and the upper limb improved the hand and wrist coordination in patients following a stroke. Placing patients in a supine position with the stability of the affected upper limb during rehabilitation exercises may help them to access latent movement patterns lost due to neurological impairment after a stroke.

Stable to unstable differences in force-velocity-power profiling during chest presses and squats

Despite several studies investigating the effect of instability resistance exercises on neuromuscular performance, the force-velocity-power characteristics of muscles involved in lifting tasks and the underlying mechanisms have not been fully explored. This study investigates power-velocity and force-velocity relationships during resistance exercises performed on stable and unstable surfaces with different weights. A group of 63 physically active young men performed chest presses on the bench and Swiss ball, and squats on the firm surface and BOSU ball with weights from 20 kg to at least 85% of one-repetition maximum. Peak and/or mean values of power, velocity and force were analyzed. Results showed significantly lower peak power and force during chest presses on the Swiss ball as opposed to the bench at lower velocities (147.6 W and 176.0 N at 1.1 m·s^-1, 108.7 W and 126.4 N at 1.3 m·s^-1, 112.0 W and 72.7 N at 1.5 m·s^-1; all at p < 0.01). Their values produced at lower velocities were also significantly lower during squats on the BOSU ball when compared to the firm surface (232.2 W and 257.1 N at 1.1 m·s^-1, 228.2 W and 173.3 N at 1.2 m·s^-1, 245.1 W and 156.8 N at 1.3 m·s^-1, 254.5 W and 113.5 N at 1.4 m·s^-1; all at p < 0.05). These significant differences between power produced during stable and unstable resistance exercises at lower velocities (or at higher loads) have to be taken into account in sports that require production of a high force in a short time. Because of the variable loading patterns under unstable conditions, it is necessary to quantify the optimal exercise load for each individual athlete.

Relationship of Barbell and Dumbbell Repetitions With One Repetition Maximum Bench Press in College Football Players

ABSTRACT

Heinecke, ML, Mauldin, ML, Hunter, ML, Mann, JB, and Mayhew, JL. Relationship of barbell and dumbbell repetitions with one repetition maximum bench press in college football players. J Strength Cond Res 35(2S): S66-S71, 2021-Dumbbell training to augment barbell training is gaining popularity. However, information is lacking that details the compatibility of strength and endurance between dumbbell and barbell performances in the same exercise. Therefore, the purposes of this study were to compare the similarity of muscular endurance performance between dumbbell and barbell exercises and to assess the accuracy of predicting one repetition maximum (1RM) barbell bench press from barbell and dumbbell repetitions to fatigue (RTF). College football players (n = 40) performed 1RM barbell bench press and RTF with a 90.9-kg barbell. On separate days, unilateral (45.5 kg) and bilateral dumbbell (90.9 kg) RTF were performed. Barbell RTF (13.8 ± 9.2) were significantly greater (effect size [ES] = 0.14) than bilateral dumbbell RTF (12.5 ± 9.5) but highly correlated (r = 0.96). Unilateral dumbbell RTF were significantly greater (ES = 0.13) for dominant hand (10.8 ± 10.1) than nondominant hand (9.5 ± 9.7) but highly correlated (r = 0.97). Prediction of 1RM barbell bench press was equally effective using a constant weight barbell (r = 0.90) or equivalent weight bilateral dumbbells (r = 0.87) with total errors of 7.3 and 8.2%, respectively. Barbell and dumbbell repetitions with equivalent weights place a similar demand on the upper-body musculature for training and testing purposes in football athletes.

Non-local acute stretching effects on strength performance in healthy young adults

BACKGROUND

Static stretching (SS) can impair performance and increase range of motion of a non-exercised or non-stretched muscle, respectively. An underdeveloped research area is the effect of unilateral stretching on non-local force output.

OBJECTIVE

The objective of this review was to describe the effects of unilateral SS on contralateral, non-stretched, muscle force and identify gaps in the literature.

METHODS

A systematic literature search following preferred reporting items for systematic review and meta-analyses Protocols guidelines was performed according to prescribed inclusion and exclusion criteria. Weighted means and ranges highlighted the non-local force output response to unilateral stretching. The physiotherapy evidence database scale was used to assess study risk of bias and methodological quality.

RESULTS

Unilateral stretching protocols from six studies involved 6.3 ± 2 repetitions of 36.3 ± 7.4 s with 19.3 ± 5.7 s recovery between stretches. The mean stretch-induced force deficits exhibited small magnitude effect sizes for both the stretched (-6.7 ± 7.1%, d = -0.35: 0.01 to -1.8) and contralateral, non-stretched, muscles (-4.0 ± 4.9%, d = , 0.22: 0.08 to 1.1). Control measures exhibited trivial deficits.

CONCLUSION

The limited literature examining non-local effects of prolonged SS revealed that both the stretched and contralateral, non-stretched, limbs of young adults demonstrate small magnitude force deficits. However, the frequency of studies with these effects were similar with three measures demonstrating deficits, and four measures showing trivial changes. These results highlight the possible global (non-local) effects of prolonged SS. Further research should investigate effects of lower intensity stretching, upper versus lower body stretching, different age groups, incorporate full warm-ups, and identify predominant mechanisms among others.

Longitudinal analysis of the recovery of trunk control and upper extremity following stroke: An individual growth curve approach

Background and Purpose: Trunk control is thought to contribute to upper extremity function. It is unclear whether recovery of trunk control has an impact on the recovery of the upper extremity in people with stroke. This longitudinal study monitored the recovery of trunk control and upper extremity in the first 6 months following stroke.Methods: Forty-five participants with stroke were assessed monthly for 6 months following stroke. Trunk control was assessed using the Trunk Impairment Scale (TIS); upper extremity impairment and function were assessed with the Fugl-Meyer (FMA) and Streamlined Wolf Motor Function Test (SWMFT) respectively. The SWMFT included the performance time (SWMFT-Time) and functional ability scale (SWMFT-FAS). The individual growth curve modeling was used to analyze the longitudinal data.Results: The recovery curve of TIS, FMA, SWMFT-Time and SWMFT-FAS followed a quadratic trend, with the rate of recovery decreasing from the first to sixth month. As TIS score improved over time, FMA, SWMFT-Time and SWMFT-FAS improved in parallel with the TIS score. TIS at each time point was found to be a significant predictor of FMA, SWMFT-Time and SWMFT-FAS at 6 months post stroke.Conclusion: Our work has provided, for the first time, substantial evidence that the pattern of recovery of trunk control is similar to that of the recovery of upper extremity following stroke. In addition, this study provides evidence on which to design a prospective study to evaluate whether improvement in trunk control early post-stroke results in better long-term upper extremity function.

Effect of Unstable Loads on Stabilizing Muscles and Bar Motion During the Bench Press

ABSTRACT

Lawrence, MA, Ostrowski, SJ, Leib, DJ, and Carlson, LA. Effect of unstable loads on stabilizing muscles and bar motion during the bench press. J Strength Cond Res 35(2S): S120-S126, 2021-Unstable loads are anecdotally used to increase muscle stabilizer strength and utilization; however, there is little evidence to support these claims. Twelve male powerlifters (age 28.6 ± 5.2 years, body mass 105.6 ± 14.5 kg, lifting experience 9.8 ± 6.0 years, and bench press 5 repetition maximum [5RM] 133.6 ± 30.9 kg) pressed their 5RM in one stable condition with a standard barbell, and 3 unstable conditions using a flexible barbell with weights suspended from elastic bands. Mean integrated muscle activity for each repetition of the stabilizers and prime movers were measured. A Lyapunov exponent and sample entropy indicated unstable loads were less predictable and more variable in the superior/inferior direction, thus more challenging to control, despite decreased loads. The main finding was increased bicep activity in all unstable conditions (light bands and plates, +57%; mini bands and plates, +67%; and mini bands and kettlebells, +88%). Although less weight was used in the unstable 5RMs, most stabilizer muscle activity was not different between conditions, suggesting that the amount of weight used during unstable load training (up to 32.3% less load) may be limited by the ability of stabilizer muscles to control the load.

Effects on Strength, Power and Speed Execution Using Exercise Balls, Semi-Sphere Balance Balls and Suspension Training Devices: A Systematic Review

Research in instability has focused on the analysis of muscle activation. The aim of this systematic review was to analyse the effects of unstable devices on speed, strength and muscle power measurements administered in the form of controlled trials to healthy individuals in adulthood. A computerized systematic literature search was performed through electronic databases. According to the criteria for preparing systematic reviews PRISMA, nine studies met the inclusion criteria. The quality of the selected studies was evaluated using STROBE. The average score was 14.3 points, and the highest scores were located in ‘Introduction’ (100%) and ‘Discussion’ (80%). There is great heterogeneity in terms of performance variables. However, instability seems to affect these variables negatively. The strength variable was affected to a greater degree, but with intensities near to the 1RM, no differences are observed. As for power, a greater number of repetitions seems to benefit the production of this variable in instability in the upper limb. Instability, in comparison to a stable condition, decreases the parameters of strength, power, and muscular speed in adults. The differences shown are quite significant in most situations although slight decreases can be seen in certain situations.

Association between core stability and physical function, functional performance in patients with systemic sclerosis

OBJECTIVE

To investigate the association of core stability with physical function and functional performance in patients with systemic sclerosis (SSc).

METHODS

Forty patients who met the American College of Rheumatology / European League Against Rheumatism 2013 classification criteria for SSc were included in the cross-sectional study. For evaluation of core stability, trunk muscle endurance and trunk muscle strength were assessed. Trunk extensor and trunk flexor endurance tests were used for assessment of trunk muscle endurance. Trunk muscle strength was measured with a hand-held dynamometer and modified sit-up test. To measure physical function the Health Assessment Questionnaire Disability Index (HAQ-DI) and to measure functional performance 6-minute walking test (6MWT) and sit-to-stand test (STS) were used.

RESULTS

Patients with SSc had lower mean trunk extensor and flexor endurance test times (49.87 ± 30.81 and 32.17 ± 15.42 seconds, respectively), modified sit-up test repetition (17.42 ± 7.81) and trunk extensor and flexor muscle strength (7.48 ± 2.29 kg and 6.20 ± 1.68 kg, respectively) when compared to the reference values in healthy individuals. All measurements were used to evaluate core stability associated with HAQ-DI score, 6DMWT walking distance and STS test duration (all P < .05).

CONCLUSION

Patients with SSc have markedly reduced core stability and this negatively affects the physical function and functional performance. Therefore, this study highlights the importance of trunk muscle in patients with SSc. We suggest that not only upper-lower extremity muscles, but also trunk muscle strength and endurance should be measured and core stability exercises can be added to the training programs to maintain and/or improve physical functions and functional performance in SSc patients.

Balance Training Reduces Postural Sway and Improves Sport-specific Performance in Visually Impaired Cross-Country Skiers

ABSTRACT

Kurz, A, Lauber, B, Franke, S, and Leukel, C. Balance training reduces postural sway and improves sport-specific performance in visually impaired cross-country skiers. J Strength Cond Res 35(1): 247-252, 2021-Balance training is highly effective in reducing sport injuries and causes improvements in postural stability and rapid force production. So far, the positive effects of balance training have been described for healthy athletes. In the present experiments, we questioned whether athletes with disabilities of the visual system can also benefit from balance training. Fourteen visually impaired cross-country skiers participated in this randomized controlled study. The intervention group (N = 7) completed 8 sessions of balance training over a period of 4 weeks (2 times per week), whereas a waiting control group (N = 7) received no training during that time. After training, postural sway was significantly reduced in the intervention group but not in the waiting control group. In addition, sport-specific performance, which was assessed by a standardized Cooper's 12-minute test on roller skis or rollerblades, increased in the intervention group. The change in postural sway from the premeasurement to the postmeasurement correlated with the change in sport-specific performance in all subjects. Our results indicate that balance training is useful for improving postural stability and sport-specific performance in visually impaired cross-country skiers. We propose that balance training should therefore be implemented as part of the training routine in athletes with disabilities of the visual system.

Effects of Trunk Exercise on Unstable Surfaces in Persons with Stroke: A Randomized Controlled Trial

Background: Improving balance-related ability is an important goal in stroke rehabilitation. Evidence is needed to demonstrate how this goal could be better achieved. Aim: Determine if trunk exercises on unstable surfaces would improve trunk control and balance for persons in the subacute stage of stroke. Design: An assessor-blind randomized controlled trial. Setting: Inpatients in the department of rehabilitation in a general hospital. Population: Patients who suffered a first-time stroke with onset from one to six months. Methods: Inpatients with stroke were assigned to upper limb exercises (control group, n = 17) or trunk exercises on unstable surfaces (experimental group, n = 18) to receive training twice a week for six weeks, in addition to their daily conventional stroke rehabilitation. Sensorimotor function tests, including hand grip, plantar sensitivity, stroke rehabilitation assessment of movement and Fugl-Meyer lower extremity motor scale, and clinical outcome assessments, including Trunk Impairment Scale and 6 m walk test, were conducted before and after six weeks of training. The center of the pressure area while maintaining static posture and peak displacement while leaning forward, as well as the average speed of raising the unaffected arm, were measured in sitting without foot support, sitting with foot support and standing to reflect trunk control, sitting balance and standing balance, respectively. Results: The between-group differences in the sensorimotor functions were nonsignificant before and after training. Compared with the control group, the experimental group had significantly greater forward leaning and faster arm raising in sitting without foot support, higher Trunk Impairment Scale total score, and shorter 6 m walking time after training, but not before training. Conclusion: Trunk exercises on unstable surfaces could further improve trunk control, the ability to raise the unaffected arm rapidly in sitting, and walking for persons in the subacute stage of stroke. This intervention may be considered to be included in stroke rehabilitation.

CONSIDERATION OF SPORT DEMANDS FOR AN 18-YEAR-OLD LACROSSE PLAYER WITH RECALCITRANT SYMPTOMATIC SPONDYLOLYSIS: A CASE REPORT

Background and Purpose

Spondylolysis is an anatomical defect or fracture of the pars interarticularis and encompasses almost half of all cases of low back pain in adolescent athletes. Most athletes return to sport with conservative treatment, but it is possible that consideration of sport demands may further improve rate of successful return. When surgery is performed, complication rate is high, so all conservative measures should be explored before considering surgical intervention. The purpose of this case report is to present a program where demands of sport were considered and allowed successful return to sport for a subject with recalcitrant symptomatic spondylolysis that had failed to respond to prior treatment.

Case Description

An 18-year-old lacrosse player with a history of recalcitrant symptomatic spondylolysis that failed three courses of conservative treatment and had been unsuccessful in returning to sport. A multi-phase program with a focus on multi-planar and full kinetic chain activities that addressed the nature of the sport demands is described, along with improvements in pain level, strength, range of motion, and subjective outcome scores.

Outcomes

The subject was able to successfully return to sport after 10 weeks of physical therapy and complete the remaining few months of his lacrosse season without reinjury. Range of motion and strength testing was markedly improved upon discharge. The subject's Modified Oswestry Disability Index improved from 16% to 0% and his pain level did not rise above 2/10 with any sport activity upon return.

Discussion/Conclusions

Although return to sport rates following spondylolysis in young athletes is high, this case report demonstrates that a consideration of sport demands may increase return to sport rates in athletes that do not respond to standard care and prevent surgical intervention.

Level of Evidence

Level 4, single case report.

Sport-Specific Differences in Power–Velocity–Force Profiling during Trunk Rotations at Different Loads

This study investigates differences in power and velocity at different loads and power and force at different velocities during trunk rotations in athletes who practice sports with rotational demands on the trunk. Athletes of combat (n = 23), fighting (n = 39), ball (n = 52) and water sports (n = 19) with a mean age of 23.8 ± 1.5 years performed standing trunk rotations on each side with bars of different weights (from 1 kg up to 50 kg) placed on their shoulders. The findings showed significant between-group differences in mean power in the acceleration phase of trunk rotations, especially at higher weights (≥10.5 kg) or lower velocities (≤334.2 rad/s). The power at 10.5 kg was significantly higher in fighting than water (p = 0.035; d = 0.86), combat (p = 0.001; d = 1.53) and ball sports athletes (p = 0.001; d = 1.48), with no significant differences between the two latter groups; at 15.5 kg, it was higher in water than combat (p = 0.027; d = 0.91) and ball sports athletes (p = 0.009; d = 1.17) but not those in fighting sports; and at 20 kg, it was higher in water than combat (p = 0.013; d = 0.98) and ball sports athletes (p = 0.006; d = 1.33), with no significant differences with those in fighting sports. This testing is sensitive in discriminating between athletes of various sports, which may reflect the specificity of their training, including trunk rotations at various velocities under different load conditions.

Effects of trunk extensor eccentric exercise on lipid profile and glycaemic response

Objectives

A number of previous studies reported physiological responses and adaptations after eccentric muscle contraction of limb muscles. In contrast, no study has determined physiological response after eccentric contraction of trunk muscles. The purpose of the present study was to compare the functional and metabolic changes after eccentric or concentric exercises of trunk extensor muscles.

Methods

In this randomised, crossover study, 10 men performed a single bout of 50 maximal voluntary concentric and eccentric contractions of the trunk extensor with an interval of 2 weeks between bouts. The activities of the paraspinal muscles were recorded during concentric and eccentric contractions. Muscle soreness, muscle function, blood lipid profiles and glycaemic responses were measured before, immediately after and at 24, 48, 72 and 96 hours after each bout.

Results

The lumbar multifidus and iliocostalis lumborum activities during eccentric contractions were significantly higher than those during concentric contractions (p<0.05). The maximal strength and muscle endurance of the trunk extensor were not decreased even after the eccentric contractions. Compared with concentric contractions, muscle soreness was significantly increased at 24, 48, 72 and 96 hours after eccentric contractions (p<0.05). The TG, TC and LDL-C were significantly lower at 48, 72 and 96 hours after eccentric contractions (p<0.05), while blood glucose levels and HOMA-IR were significantly greater at 48 and 72 hours after eccentric contractions (p<0.05).

Conclusion

This study indicated that eccentric contractions of the trunk extensor had positive effects on the lipid profile and the glycaemic response.

Second Wave of COVID-19 Global Pandemic and Athletes' Confinement: Recommendations to Better Manage and Optimize the Modified Lifestyle

Coronavirus 2019 (COVID-19) is an infectious viral disease that has spread globally, resulting in the ongoing pandemic. Currently, there is no vaccine or specific treatment for COVID-19. Preventive measures to reduce the chances of contagion consist mainly of confinement, avoiding crowded places, social distancing, masks, and applying strict personal hygiene as recommended by the World Health Organization (WHO). After the first wave of infection in many countries, the potential effects of relaxing containment and physical distancing control measures suggest that as a result of these measures, a second wave of COVID-19 appears probable in these countries. In sport, the period of self-isolation, and quarantine, for COVID-19 affects the physical preparation of athletes as well as their mental health and quality of life to an even greater extent (i.e., nutrition, sleep, healthy lifestyle), and thus, relevant and practical recommendations are needed to help alleviate these physical and mental health concerns. Our review aims to summarize the physiological and psychological effects of detraining associated with athletes' confinement during the proposed second wave of COVID-19. This article also proposes answers to questions that concern the advantages and disadvantages of different types of social media platforms, the importance of nutrition, and the effects of sleep disturbance on the health and modified lifestyle of athletes during this worldwide pandemic. Thus, this review provides some general guidelines to better manage their modified lifestyle and optimally maintain their physical and mental fitness with respect to measures taken during this restrictive proposed second wave of the COVID-19 confinement period.

The effect of static and dynamic core exercises on dynamic balance, spinal stability, and hip mobility in female office workers

Objectives

This study aims to compare the effect of static and dynamic core exercises in terms of dynamic balance, spinal stability, and hip mobility in female office workers.

Patients and methods

Between May 2018 and June 2018, a total of 34 women (mean age 36.4±6.5 years; range, 28 to 54 years) who worked for a bank and exercised in the fitness center of the work place were recruited. The women were divided into two groups including 17 women in each as static and dynamic core groups and administered sessions of 20 to 30 min twice a week for six weeks. Both groups were tested for dynamic balance (Y-balance test), spinal stability (functional reach test), and hip mobility (active flexion and extension) before and after six weeks of exercise.

Results

A statistically significant improvement was found in both groups between the pre- and post-test results in terms of spinal stability, hip mobility, and dynamic balance (p<0.05). The only exception was the right and left leg anterior balance in the static core group. Dynamic core exercises seemed to be more effective than static core exercises in improving the right and left leg anterior balance. There were no statistically significant differences between the groups in terms of spinal stability, hip mobility, and dynamic balance according to the mean absolute change (p>0.05).

Conclusion

Our study results indicate that both types of exercises are effective in improving dynamic balance, spinal stability, and hip mobility in female office workers. Therefore, the expected benefits from core exercises are to enhance dynamic balance, spinal stability, and hip mobility. Female workers can perform both types of exercises safely and effectively.

Influence of Abdominal Hollowing Maneuver on the Core Musculature Activation during the Prone Plank Exercise

This cross-sectional study of repeated measures investigated whether integrating the abdominal hollowing maneuver (AHM) into the prone plank performance is an effective strategy for increasing both the activation of the deep and superficial core musculature. Electromyographical (EMG) responses of rectus abdominis (RA), external oblique (EO), internal oblique (IO), and lumbar erector spinae (LES), and ratings of perceived exertion (RPE) of 20 participants (13 male, 7 female; mean ± standard deviation (SD) age: 24.25 ± 3.54 years; body mass: 66.42 ± 8.40 kg; height: 1.70 ± 9.51 m) were compared across two experimental conditions: the traditional prone plank (STANDARD); and a variation including the AHM (HOLLOWING). Regarding Total Intensity, HOLLOWING resulted in significantly greater EMG response than STANDARD (p < 0.001; Effect size (ES) = 3.01). Specifically, RA showed no significant differences between STANDARD and HOLLOWING (p = 0.056; ES = 0.285). However, for the remaining analyzed muscles, HOLLOWING significantly provided higher EMG activation compared to STANDARD (LES: p = 0.004; ES = 0.619; left EO: p < 0.001; ES = 1.031; right EO: p < 0.001; ES = 1.419; left IO: p < 0.001; ES = 2.021; right IO: p < 0.001; ES = 2.269). Regarding RPE, HOLLOWING reported values significantly greater than STANDARD (p < 0.001; ES = 2.94). In conclusion, integrating the AHM into the prone plank exercise enhances overall abdominal activity, particularly in both obliques. These findings provide updated guidelines for lumbar stabilization and core strengthening in health-related physical fitness programs.

Effect of a Six-Week Core Conditioning as a Warm-Up Exercise in Physical Education Classes on Physical Fitness, Movement Capability, and Balance in School-Aged Children

Whether the implementation of feasible, equipment-free, and simple core exercises in warm-up routines in physical education classes for school-aged children is beneficial remains unclear. Therefore, this study investigated the effects of a core conditioning in the warm-up routine of physical education classes on trunk muscular endurance, movement capability, and flexibility in this population. In these pre- and post-test control group experiments, 52 healthy, school-aged children (aged 10-11 years) were cluster randomized allocated to either the dynamic core exercise (DCE) group or general physical education (GPE) group. The DCE group performed a 10-min core exercise routine twice per week for six consecutive weeks; the GPE group performed traditional physical education warm-up exercises regularly. The children were assessed by conducting the trunk muscular endurance test (i.e., dynamic curl-up, static curl-up, plank, and lateral plank), functional movement screen (FMS), and single-leg balance test before and after the intervention. At the end of the intervention, the DCE group demonstrated a significant effect on trunk muscular endurance, movement capability (i.e., FMS scores), flexibility, and balance (each p < 0.001, effect size: 0.38-1.3). Furthermore, the DCE group showed significant improvements in all outcome measurements compared with the GPE group (p < 0.05, effect size: 0.29-1.68). These data may provide a reference for incorporating additional core stability exercises in the warm-up routine of physical education classes in school-aged children in the future.