Acute effects of whole-body vibrations on the fatigue induced by multiple repeated sprint ability test in soccer players

Temporal patterns of fatigue in repeated sprint ability testing in soccer players and acute effects of different IHRs: a comparison between genders

BACKGROUND

Repeated sprint ability (RSA) in soccer is deemed fundamental to ensure high level of performance. The aim of this study was to investigate the acute effects of two different Initial Heart Rates (IHR) on fatigue when testing RSA in males and females' soccer players and to compare the respective patterns of fatigue.

METHODS

Nineteen female soccer players (age: 22.5±3.3 years, height 163.9±7.3 cm, body weight 54.3±6.4 kg, BMI 20.6±1.5 kg·m^-2) and 15 male soccer players (age: 17.9±1.5 years, height 175.9±5.8 cm, body weight 68.5±9.6 kg, BMI 22.3±1.5 kg·m^-2) participated in this study. HRs reached at the end of two different warm-up protocols (~90 vs. ~ 60% HR<inf>max</inf>), have been selected and the respective RSA performances were compared, within and between the groups of participants. Two sets of ten shuttle-sprints (15+15 m) with a 1:3 exercise to rest ratio with different IHR% were administered, in different days, in randomized order. To compare the different sprint performances, we employed the calculated Fatigue Index (FI%). Blood lactate concentration (BLa^-) was also measured before and after testing, to compare metabolic energy.

RESULTS

Significant differences among trials within each set (P<0.01) were found in both genders. Differences between sets were found in male players, (Factorial ANOVA 2x5; P<0.001), not in female. BLa^- after warm-up was higher in 90% vs. 60% HR<inf>max</inf> (P<0.05), in both genders but at the completion of RSA tests (after 3 minutes) the differences were not significant (P>0.05).

CONCLUSIONS

difference between genders were found, suggesting specific approach in testing and training RSA in soccer players.

Whole-body vibration as a passive alternative to exercise after myocardial damage in middle-aged female rats: Effects on the heart, the brain, and behavior

Background

Females with cardiovascular disease seem more vulnerable to develop concomitant mental problems, such as depression and cognitive decline. Although exercise is shown beneficial in cardiovascular disease as well as in mental functions, these patients may be incapable or unmotivated to perform exercise. Whole body vibration (WBV) could provide a passive alternative to exercise. Aim of the present study was to compare WBV to exercise after isoproterenol (ISO)-induced myocardial damage in female rats, regarding effects on heart, brain and behavior.

Methods

One week after ISO (70 mg/kg s.c., on 2 consecutive days) or saline injections, 12 months old female rats were assigned to WBV (10 minutes daily), treadmill running (30 minutes daily) or pseudo intervention for 5 weeks. During the last 10 days, behavioral tests were performed regarding depressive-like behavior, cognitive function, and motor performance. Rats were sacrificed, brains and hearts were dissected for (immuno)histochemistry.

Results

Significant ISO-induced cardiac collagen deposition (0.67 ± 0.10 vs 0.18 ± 0.03%) was absent after running (0.45 ± 0.26 vs 0.46 ± 0.08%), but not after WBV (0.83 ± 0.12 vs 0.41 ± 0.05%). However, WBV as well as running significantly reduced hippocampal (CA3) collagen content in ISO-treated rats. Significant regional differences in hippocampal microglia activity and brain derived neurotrophic factor (BDNF) expression were observed. Significant ISO-induced CA1 microglia activation was reduced after WBV as well as running, while opposite effects were observed in the CA3; significant reduction after ISO that was restored by WBV and running. Both WBV and running reversed the ISO-induced increased BDNF expression in the CA1, Dentate gyrus and Hilus, but not in the CA3 area. Whereas running had no significant effect on behavior in the ISO-treated rats, WBV may be associated with short-term spatial memory in the novel location recognition test.

Conclusion

Although the female rats did not show the anticipated depressive-like behavior or cognitive decline after ISO, our data indicated regional effects on neuroinflammation and BDNF expression in the hippocampus, that were merely normalized by both WBV and exercise. Therefore, apart from the potential concern about the lack of cardiac collagen reduction, WBV may provide a relevant alternative for physical exercise.

Effect of Vibration Massage and Passive Rest on Recovery of Muscle Strength after Short-Term Exercise

Background: The aim of the study was to compare the effect of vibration massage and passive rest on accelerating the process of muscle recovery after short-term intense exercise. Methods: Eighty-four healthy men aged 20 to 25 years participated in the study. Study participants performed isometric (ISO-M Group) and auxotonic (AUX-M group) contraction exercise in the lower limbs. Vibration massage was administered after exercise in the first recovery period. In the same period, controls rested passively, without the support of vibration massage. To assess the effectiveness of the applied vibration, a 4-fold measurement of the maximum force of the muscles involved in the exercise was performed under conditions of isometric contractions on a leg press machine set at an angle of 45° degrees upwards. Results: Differences in maximum strength during isometric contraction were found compared to baseline in favor of the groups subjected to the experimental vibration massage. Differences were demonstrated in muscle strength between the study groups (p < 0.005). The second period of passive rest in all groups did not bring significant changes in the values of maximal lower limb strength. Conclusions: Properly selected characteristics of the vibration effect can be an effective method in accelerating recovery and regaining lost motor capabilities of muscle groups fatigued by exercise. This offers the potential to shorten rest periods between sets of repetitions in training or between training units.