The effect of 8-week PNF training on muscle damage

• Main Authors: Che-Hsiu Chen, 陳哲修
• Other Authors: 陳忠慶
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/34322241271700346544

碩士 === 國立嘉義大學 === 體育與健康休閒研究所 === 95 === Abstract Background: Unaccustomed eccentric exercise can cause significantly muscle damage to skeletal muscles. Although multiple strategies such as physiatrics, pharmacological, and nutritional supplements have been introduced to the remedy for the symptoms of muscle damage, few have scientific support. Most previously studies have focused on the post-exercise interventions and treating for the muscle damage, but there are little studies proving the prevention of muscle damage from pre-exercise, especially on the effect of long-term stretching training on reducing the extent of muscle injury. Purpose: This study was to examine whether 8-week of proprioceptive neuromuscular facilitation (PNF) training would be protect against muscle damage from a subsequent maximal isokinetic eccentric exercise. Methods: Twenty-four healthy male university students were recruited in the study, and then were randomly allocated to PNF (n=12) and control groups (CON; n=12) according to their pre-maximal isometric strength (MVC). Before the eccentric exercise, the PNF group was trained on their right leg of hamstring muscles for 8 weeks (3 days per week, once lasted 5 and 7 minutes for static stretch and PNF, respectively), but the CON group did not received any stretching treatment at this movement. Afterwards, all subjects performed a bout of 60 maximal isokinetic eccentric contractions (ECC) of the knee flexors at an angle velocity of 30°/s to cause significantly muscle damage. MVC, isokinetic concentric strength (ISO), passive range of motion of hip (P-ROM), muscle soreness, plasma creatine kinase (CK) activity, myoglobin (Mb) concentration and ultrasound images were measured before, immediately after, and for 5 days after ECC. Data were analyzed with a 2-way mixed model analysis of variance (ANOVA) with repeated measures over time and grouped as a between-subjects factor. Results: There was a significant improved (p <.05) P-ROM after 8-week PNF training compared to baseline. There were not significant changes (p >.05) in MVC, ISO, P-ROM, DOMS, CK, and Mb after ECC between the PNF and CON groups. However, the changes in muscle thickness and echo-intensity after ECC for the PNF group was a significant smaller (p <.05) than the CON group. Conclusion: The findings of the present study showed that 8-week PNF training may have a potent prevention for some indicators of muscle damage (muscle thickness and echo-intensity) to a subsequent maximal eccentric exercise. Therefore, the long-term stretching training would have a protective effect on the extent of exercise-induced muscle damage. Keywords: stretching exercise, passive range of motion, ultrasound images.