S Ilbeigi, M.r Poorbahram, M Saghebjoo,
Volume 17, Issue 17 (4-2019)
Abstract
Purpose:The aim of this study was to investigate the effect of muscle soreness due to the plyometric exercises on leg muscle EMG activity after concentric and eccentric contractions in untrained people. 20 students from untrained male students (at least 6 months out of practice), were randomly assigned to experimental (n=10) and control (n=10) groups. At pre-test, surface electromyographic activity of gastrocnemius muscle were recorded using by the Biovision 18 channel device during the both concentric (squat / plantar flexion of the ankle) and eccentric (wirepuller / ankle dorsiflexion) contractions. Then, in order to build muscle soreness, experimental group exerted 10 minutes selected plyometric exercises, while the control group did not have any training. Finally, immediately after protocol training and also after 48 hours the same record was done. Data were analyzed by Dasylab and Matlab software, and the ANOVA Repeated Measure and Bonferroni post hoc also were used for statistical analysis at a significance level of P≤0/05. The results showed that fatigue resulting from plyometric exercises, could have significant reduction in activity of gastrocnemius muscle immediately and 48 hours after exercise during eccentric contraction (P=0/001), while it was not true for concentric. According to the results, the risk of eccentric contraction could be considered for untrained people during training.
Hossein Nabavinik, Mohsen Ali Darchini, Reza Azimi,
Volume 20, Issue 23 (9-2022)
Abstract
Introduction and Objective: Core stability and plyometric exercises are training methods that athletes use to improve their performance. The purpose of this study was exploring the effect of a period of six week plyometric and core stability exercise on some of physical fitness of boy's athlete. Methods: 36 male athletes who were male with 11-14 years old participated in the semi-experimental study. They randomly divided in three group that each group has 12 subjects (first group; core stability exercise, second group; plyometric exercise and third group; control). The performance tests (standing broad Jump, Vertical Jump, 9.1 m Sprint, Shuttle Run, Flexibility and seated medicine ball toss tests) applied a day before starting core stability and plyometric exercises. Then post-test applied. In order to analysis data, ANOVA test was used (p<0.05). Results: Both core stability and plyometric exercise group showed significance increase in performance tests (Standing Broad Jump, Vertical Jump, 9.1 m Sprint, Shuttle Run). Conclusion: Based on the findings, we recommend the core stability and plyometric exercises in order to improve some of physical fitness of athletes.
Negin Gilsamaei, Dr Seyd Sadredin Shojaedin, Dr Hassan Sadeghi,
Volume 20, Issue 24 (3-2023)
Abstract
The prevalence of sports injuries in martial arts is high. Most Taekwondo injuries also occur in the lower extremities. The aim of this study is to compare the effect of a period of plyometric exercises, with and without stretching exercises, on knee valgus dynamics, flexibility and functional variables of elite female taekwondo athletes at risk of anterior cruciate ligament injuries. 45 elite female taekwondo athletes aged 15-25 years with anterior cruciate ligament injuries participated in this study. Knee valgus dynamics in squat movement were measured with KINOVEA software. Flexibility was measured with direct leg lift test and performance indicators were measured with Y-balance, three-step jump and error scoring system. The tests were conducted before and after eight weeks of plyometric exercises, along with the stretching exercises. Then, the data obtained were analyzed.There was a significant difference between the results of pre-test and post-test data measured in the two experimental groups (P ≥ 0.05). According to the stark differences based on the analyzed data, it is clearly evident that the group of athletes with plyometric exercises with stretching have obtained far superior results and outcome..Plyometric exercises with stretching had a significant effect on reducing the risk of injury, as well as increasing the flexibility and performance of elite female taekwondo athletes exposed to anterior cruciate ligament injury. Considering the vast improvements reported for the plyometric training group with stretching, it is recommended that these interventions be used to reduce the risk of injury and increase the performance of taekwondo practitioners.
