Mirror Cross-Exercise on a Kinetic Chain Approach Improves Throwing Performance in Professional Volleyball Athletes With Scapular Dyskinesis.

CONTEXT: Volleyball players have shown to be at an increased risk of developing scapular dyskinesis. The kinetic chain exercise approach has gained a lot of attention because of its claims to provide an improved motor control and scapular kinematics. A form of cross exercise, known as mirror therapy, may enhance the effects of a kinetic chain exercise approach in throwing performance. OBJECTIVE: To examine the effects of mirror cross exercise (MCE), based on a kinetic chain exercise approach in the throwing performance of volleyball athletes with scapular dyskinesis. DESIGN: Randomized controlled trial. SETTING: Biomechanics laboratory. METHODS: 39 volleyball players with scapular dyskinesis were randomly allocated into 3 groups. The first group completed a 6-week kinetic chain approach (KCA group), the second group completed a kinetic chain exercise approach program in addition to MCE group, and the control group followed only their regular training program. Before and after delivering both interventions, throwing accuracy, speed, and force were determined while measuring the ground reaction forces of the drive leg during throwing. Two-way mixed analysis of variance investigated the effects of intervention and time and their interaction. RESULTS: The results showed intervention × time statistically significant interactions for throwing accuracy, speed, and force for the MCE and the KCA groups. Over the 6-week training period, the MCE and the KCA groups showed significant improvements in throwing accuracy (P < .01) and speed (P < .01), while the ground reaction forces did not change (P > .05). Throwing force increased significantly in the MCE group (P = .01). Between-group comparison showed statistically significant improvements in the throwing accuracy for the MCE and KCA groups against the control group (P < .01) at posttesting. The MCE demonstrated superior results over the KCA in the aforementioned measures. CONCLUSIONS: This study suggests that the addition of MCE in a KCA program enhances energy transfer throughout the distal and proximal segments, thus improving kinetic chain recruitment and potentially preventing shoulder pathology.

Delayed Effect of Dry-Land Strength Training Sessions on Swimming Performance.

The purpose of the study was to examine the effects of dry-land strength endurance (SE) and maximum strength (MS) sessions on next-day swimming performance. Eight swimmers (age: 18.6 ± 2.9 years) performed evening training sessions (19:00-19:40), including: (i) SE (2 × 15 - 20 repetitions, 50% of 1-RM), (ii) MS (2 × 5 repetitions, 90% of 1-RM), (iii) control (CON: no dry-land training). All sessions were followed by a 90-min swimming training (20:00-21:30). Medicine ball throw and countermovement jump, free countermovement jump and squat jump were evaluated before and after the dry-land training session and 12 h later, before a 100-m front crawl sprint (next day at 8:30 a.m.). Performance time, RPE, blood lactate and biomechanical variables in 100-m sprint were no different between conditions (time, MS: 64.70 ± 7.35, SE: 63.81 ± 7.29, CON: 64.52 ± 7.71 s, p > 0.05). Jump height was not changed before and after dry-land and before the 100-m sprint in all conditions (p > 0.05). Medicine ball throw was lower in MS compared to CON before the 100-m sprint (MS: 4.44 ± 1.11, vs. CON: 4.66 ± 1.21 m, p < 0.05). Upper-body but not lower- body muscle function may be affected by MS training. However, performance in a 100-m test is not affected by dry-land training performed 12 h earlier.

Effect of a home-based exercise training program on anthropometric characteristics and exercise performance during Covid-19 quarantine in young high-level kayak athletes.

Purpose: The Covid-19 restriction exposed most athletes to insufficient training stimuli leading to detraining. This study investigated whether a home-based exercise training program could preserve body composition and exercise performance in young high-level kayak athletes during Covid-19 restriction. Methods: Seventeen healthy young high-level kayak athletes (10 males and 7 females), aged 14.7 ± 1 yrs, participated in this study. A 7-week home-based training program was followed during Covid-19 restriction. Baseline measurements were assessed 4 weeks before Covid-19 pandemic and ended on 4 May 2020. Body composition, flexibility, isometric muscle trunk strength (Biodex), anaerobic power (30-s all-out trial), and aerobic capacity (4-min maximal test) were evaluated. Personal daily loads and wellness details were collected with AthleteMonitoring.com software. Results: Home-based exercise training program was effective to improve flexibility (9.20 ± 2.85%) and lean body mass (3.96 ± 0.89%), to maintain muscle strength, anaerobic power, body mass, and body fat percentage but insufficient to maintain aerobic capacity (- 8.96 ± 2.49%). Conclusion: The findings of the present study potentially highlight the importance of the implementation of such a program to minimize the detraining effect on young athletes during periods of movement restriction caused by pandemics.

The adjunctive benefits of mirror cross education on kinetic chain exercise approach in volleyball athletes with scapular dyskinesis.

BACKGROUND: Volleyball players as overhead athletes have the highest risk of developing scapular dyskinesis. The kinetic chain exercise-approach has gained a lot of attention because of its claims to provide an improved motor control and scapular kinematics. A form of cross exercise, known as mirror therapy, may enhance the effects of a kinetic-chain-approach on scapular posture, upper and lower limb performance. The aim of this study was to investigate the adjunctive benefits of mirror cross education in a kinetic chain approach, in volleyball athletes with SD. METHODS: Thirty-nine professional volleyball athletes were randomly assigned to three groups of 13 each, two experimental, the mirror cross education and kinetic chain approach, and one control. Both experimental groups performed a kinetic chain approach program, however, the mirror cross education group performed the exercise program with the addition of two mirrors that allowed athletes to observe their opposite non-dyskinetic scapula. Scapular posture asymmetries in cm, the Y-Balance and the Upper-Quarter Y-Balance after normalizing by limb length the reach distance in each direction, were assessed before and after performing each intervention for 6 weeks. RESULTS: 3×2 two-way Mixed ANOVAs detected significant interactions on scapular posture (P=0.001) on both experimental groups when compared with the control. The Y-Balance and the Upper Quarter Y-Balance scores at both mirror cross education and kinetic chain approach groups showed significant differences when compared with the control (P<0.05). Overall, variables showed significant superiority of the mirror cross education group. CONCLUSIONS: The Mirror-Cross-Education demonstrated significant effects in scapular posture and in the functional balance tests of volleyball athletes with scapular dyskinesis.

Validity and Reliability of New Equations for the Prediction of Maximal Oxygen Uptake in Male and Female Elite Adolescent Rowers.

The aim of this study was to develop accurate, reliable, and reproductive equations for the prediction of maximum oxygen uptake ( V ˙ O2max) in male and female high-level adolescent rowers. This study included two parts. In the first part, V̇O2max was evaluated in 106 male and 83 female high-level adolescent rowers during an incremental step test (IRT) on a rowing ergometer, and stepwise multiple regression analyses were used for the development of new equations. In the second part, these equations were tested in 26 new high-level adolescent rowers of the same age and anthropometrical characteristics (boys: 15.27 ± 2.70 yrs and 15.34 ± 2.80 yrs; 72.37 ± 10.96 kg and 70.96 ± 10.65 kg; girls: 15.00 ± 2.11 yrs and 15.94 ± 2.71 yrs; 62.50 ± 7.14 kg and 63.41 ± 6.72 kg for parts 1 and 2, respectively; p > 0.05). V̇O2max was predicted from the combination of lean body mass (LBM) and the distance covered during the last 4 min stage of the IRT (boys: r2 = 0.715, F = 68.74, p = 0.001; girls: r2 = 0.769, F = 57.81, p = 0.001). In the second part, no significant differences were identified when the new equations were tested against measured V̇O2max (boys: 3971.15 ± 713.38 mL·min-1 vs. 3915.83 ± 704.43 mL·min-1; girls: 3272.75 ± 551.46 mL·min-1 vs. 3308.94 ± 557.59 mL·min-1 for measured and predicted values, respectively; p > 0.05). In conclusion, V̇O2max of high-level adolescent rowers can be predicted with high accuracy, reliability, and repeatability using simple and easily evaluated anthropometric and performance variables.