The effects of using a combination of static stretching and aerobic exercise on muscle tendon unit stiffness and strength in ankle plantar-flexor muscles.

The purpose of the present study was to investigate the effects of using a combination of static stretching and aerobic exercise on muscle tendon unit stiffness and muscle strength in the ankle plantar-flexor muscles. Fifteen healthy males (23.3 ± 2.7 years, 170.3 ± 6.5 cm, 64.9 ± 8.7 kg) received three different interventions, in random order. Intervention 1 received 10 min of aerobic exercise after five cycles of one minute of static stretching. Intervention 2 received 10 min of aerobic exercise before the static stretching. Intervention 3 received 5 min of aerobic exercise both before and after the static stretching. The range of motion of ankle dorsiflexion, stretch tolerance, muscle tendon unit stiffness, peak torque of ankle plantarflexion, and the amplitude of electromyography were measured. In all interventions, the range of motion and stretch tolerance significantly increased (p < 0.05), but muscle tendon unit stiffness decreased significantly for all interventions (p < 0.05). Peak torque of ankle plantar flexion and amplitude of electromyography significantly increased for Interventions 1 and 3 (p < 0.05), while these significantly decreased for Intervention 2 (p < 0.05). These data indicated that range of motion and stretch tolerance were increased, but muscle tendon unit stiffness was decreased regardless of the order of static stretching and aerobic exercise. Aerobic exercise after static stretching increased the peak torque and amplitude of electromyography.

Change in dynamic postural control after a training program in collegiate soccer players with unilateral chronic ankle instability.

BACKGROUND: Improving dynamic postural stability after lateral ankle sprain due to chronic ankle instability helps prevent recurrence, and changes in dynamic postural stability can be assessed with the Star Excursion Balance Test. To date, no studies have examined the change in Star Excursion Balance Test score after the end of a balance training program or whether chronic ankle instability affects the rate of change. To examine the effect of chronic ankle instability on changes in Star Excursion Balance Test. score over time after a balance training program. METHODS: Fifteen collegiate soccer players with chronic ankle instability selected with the Cumberland Ankle Instability Tool and ultrasonography. Participants completed a 6-week balance training program. We assessed the Star Excursion Balance Test 5 times (before and immediately after the program and 2, 4, and 6 weeks later) and examined differences in the duration of training effects by a 2-way analysis of variance, with Bonferroni correction for post hoc comparisons to explain any significant interactions. The significance level for all analyses was set at P<0.05. We performed statistical analyses with SPSS v. 25. RESULTS: Analysis of the posterolateral and posteromedial scores in Star Excursion Balance Test showed a significant effect of time. Post hoc analysis of the posterolateral score showed that for each leg, participants reached significantly farther after the program than before (P=0.012). The posterolateral scores at 2, 4, and 6 weeks after the training program did not differ from before the program, but the posteromedial score was significantly improved immediately after the program (P=0.008) and also 2 (P=0.004) and 4 weeks later (P=0.006). CONCLUSIONS: A 6-week balance training program to improve dynamic postural control can improve posterolateral and posteromedial scores in people with chronic ankle instability, and the improvements in posteromedial are still present 4 weeks after program completion.

Effects of Active and Passive Warm-ups on Range of Motion, Strength, and Muscle Passive Properties in Ankle Plantarflexor Muscles.

ABSTRACT: Takeuchi, K, Takemura, M, Nakamura, M, Tsukuda, F, and Miyakawa, S. Effects of active and passive warm-ups on range of motion, strength, and muscle passive properties in ankle plantarflexor muscles. J Strength Cond Res 35(1): 141-146, 2021-The purpose of this study was to examine the effects of active and passive warm-ups on flexibility and strength of calf muscles. Fourteen healthy males (age: 23.1 ± 2.6 years, height: 172.7 ± 5.6 cm, and body mass: 64.5 ± 7.0 kg) performed 3 types of warm-ups respectively for 10 minutes in a random order: an active warm-up by pedaling a cycling ergometer, an active warm-up doing repeated isometric contractions, and a passive warm-up in a hot water bath. To assess flexibility, range of motion (ROM) of ankle dorsiflexion, passive torque of ankle plantarflexion, and muscle tendon junction (MTJ) displacement were measured and then muscle tendon unit (MTU) stiffness was calculated. After the flexibility assessment, peak torque during maximum voluntary isometric contraction was measured to assess the isometric strength. These data were compared before and after each warm-up. As a result, all 3 types of warm-ups increased ROM (p < 0.05) and passive torque at terminal ROM (p < 0.01), but there were no significant changes in MTU stiffness or MTJ displacement. The active warm-up by pedaling a cycling ergometer increased peak torque during isometric contraction (p < 0.05), whereas the other warm-ups did not show significant alterations. In conclusion, the active warm-up with aerobic exercise increased flexibility and strength of the calf muscles.

Comparison of the effects of static stretching on range of motion and jump height between quadriceps, hamstrings and triceps surae in collegiate basketball players.

OBJECTIVES: The purpose of the present study was to compare the effects of static stretching (SS) on the range of motion and vertical jump height between the quadriceps, hamstrings and triceps surae in collegiate basketball players. METHODS: Fourteen male collegiate basketball players (20.2±0.7 years, 179.0±5.0 cm, 71.9±8.3 kg) underwent 5 min of SS for the quadriceps, hamstrings and triceps surae, in random order. Before and after each stretch, the range of motion (ROM) and vertical jump height were measured. RESULTS: ROM of the quadriceps, hamstrings and triceps surae were increased without any difference of relative change in the range. The vertical jump height showed no change after SS of the quadriceps and hamstrings, while it decreased after SS of the triceps surae (p<0.05). CONCLUSION: These results suggested that SS for the triceps surae may have a large impact on jump performance.