Response Variability and Detraining Effects of Standardized Exercise Programs

Purpose: To compare inter–individual response variability and detraining effects on markers attributed to aerobic and anaerobic performance after shortterm standardized aerobic, strength and mixed training programs. Methods: Thirty–six male students were randomly assigned to either an aerobic, strength, mixed, or control program (9 per group). They performed two consecutive cycling tests (incremental and plateau) to exhaustion at three points: 1 week before training, after 6 weeks of training, and 3 weeks after the training was finished. Maximal oxygen consumption (VO2max), maximal workload (Wmax), and time to exhaustion performed at Wmax (W × time) were compared between groups by repeated–measures ANOVA with Bonferroni post–hoc tests. The inter–subject response variability within each training group was evaluated by comparison with the 95% confidence interval of the control group. Detraining effects were evaluated using the hysteresis areas, which were compared between each training group and the control group by Mann–Whitney U test. Results: Differences were observed in Wmax for the aerobic (F(2,7)=19.562; p=0.001; n²=0.85) and mixed (F(2,7)=13.447; p=0.004; n²=0.99) programs, and in W × time for the mixed program (F(2,7)=15.432; p= 0.016; n²=0.89). There was high inter–subject response variability for all variables and training programs, except for a homogenous positive response to Wmax in the mixed program (X²=6.27; p=0.04). Detraining effects of Wmax were also better maintained after the mixed program. Conclusion: A mixed program of aerobic and strength training demonstrated higher improvements in the studied markers of performance, with lower interindividual response variability, and longer detraining effects compared with aerobic or strength programs.

Analysis of Body Composition and Volleyball Performance in Athletes of the Italian Top League

Objectives: The assessment of body composition is crucial for identifying an individual’s characteristics critical to performance, evaluating the effects of training programs, managing weight strategies, and monitoring athletic health. Bioimpedance vector analysis is spreading as a method to obtain a qualitative assessment of body composition. In the present study we investigated the relationship between body composition of top-level female volleyball players and their performing data during the matches of the Italian First League Championship. Design: Observational. Method: Attackers from a volleyball team participating in the Italian 1st (Super Lega) division were monitored by bioelectric impedances performed before each match of the ON-season period and results were related to individual performance data provided for each match by the Italian Volleyball League. Results: The height of the players was confirmed as a fundamental parameter, it was related to blocked attacks, to service errors, and to attack efficiency. The athletes’ body mass showed a performance influence, too. It was correlated to blocked attacks and to the attack efficiency. The FM was correlated to the blocked attacks and with the invasion blocks. The total body water percentage was negatively related to blocks invasion. Conclusion: Any anthropometric and bioimpedance vector analysis data seems to influence the athlete’s performance during competitive matches.

The Effect of Varus Deformity on Co-Activation of Abdominal and Lower Limb Muscles during Landing Task in Female Subjects

Objective: Genuvarum deformity experience knee instability. This deformity can lead the patient to sever osteoarthritis. The recovery of postural stability is very important to prevention of these patients. Strategies aimed at stabilizing the muscle can have a long-term effect on the joint. This study was performed to determine the relationship between muscle stabilization strategies and knee instability, in order to determine how people with knee Genuvarum, respond to rapid absorption and muscle co- contraction during landing task. Methods: Twenty female participants, (10 normal and 10 Genuvarum) in the present study. The subjects were land by preferred lower limb from a table (30 cm high) on a force plate. Vertical ground reaction force, time to peak of vertical reaction force, velocity of vertical ground reaction force to reach the maximum, time to stability in X and Y directions and resultant vector were calculated as postural control parameters. Also surface electromyography of transverse abdominal/int. oblique, vastus medialis, vastus lateralis, lateral gastrocnemius, and medial gastrocnemius muscles were recorded during landing. Motor control strategy were measured by similarity index and voluntary response index. Results: There are significant difference between Genuvarum and Healthy subjects in motor control strategy (P<0.05).A significant difference are detected in postural control parameters between two groups (P<0.05). Conclusion: Genuvarum deformity may be linked to altered quadriceps, abdominal and gastrocnemius muscles reciprocal co-activation patterns during landing task. In addition, may be affected voluntary motor control strategy in synergy concepts. Postural control is affected in these deformity and shock absorption may be reduced in parallel to increase of response vector and reduce of instability in landing task.

Changes in the Trend of Walking Motor Control in Athletes with Anterior Cruciate Ligament Deficiency in Response to Progressive Perturbation Trainings

Background and Purpose: The beliefs are that sudden and unpredictable balance disturbance by instruments that cause mechanical perturbations can affect individuals with Anterior Cruciate Ligament Deficiency (ACLD) to reach faster and more effective recovery of knee dynamic stabilization strategies to return successfully pre-injury levels. The aim of this study was to investigate the effect of mechanical perturbation training and standard training in the process of changes in motor control during walking task in coper ACLD individuals. Methods: Thirty athletes with a unilateral rupture of the Anterior Cruciate Ligament (ACL), classified as coper, were randomly assigned to perturbation and standard training groups. Intervention training results based on comparison of scores obtained from functional tests in 4 single-leg jump tests, scores of questioners, and surface Electromyography (sEMG) tests were determined between the two groups as well as between the two healthy and ACLD limbs in each group in the walking task. Results: The perturbation training group showed a significant increase in muscle activity in both healthy and ACLD limbs with an increase in similarity index (SI) (p=0.08, ES=0.81), while in the standard training group the results were not significant (p=0.39, ES=0.39). Conclusion: Individuals in the perturbation training group achieved higher scores on all tests compared to the standard training group. This means that the perturbation training group was more mentally and physically prepared in terms of strength, coordination and symmetry between the two limbs to participate in pre-injury sports levels.

The Potential Effect of Conjugated Linoleic Acid on Endurance Exercise: A Mechanistic Review

Introduction: The purpose of the present study was to appraise the results from disseminated human, animal and in vitro studies, and evaluate the possible effect along with the mechanism of CLA supplementation on endurance exercise. Methods: Related articles were searched on PubMed, Web of Science, Scopus, Embase, and Cochrane databases with defined keywords. Articles were assessed through their titles and abstracts. Finally, 11 articles were included based on inclusion and exclusion criteria. Results: Most of the studies were conducted on animals, and CLA was often supplemented along with training. Dosage and study duration vary for a broad range. Results showed various possible pathways on the effect of CLA supplementation on endurance exercise and related factors. Conclusions: It was indicated that CLA supplementation could prolong endurance performance by improving oxidant status, mitochondrial biogenesis, testosterone biosynthesize, fat oxidation, and change in body composition. Although CLA is being used in many countries and numerous studies have shown its safety, its long-term supplementation and effect need to be investigated. Also, further studies are required to identify the molecular mechanism in the human body.