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Acute effect of downhill running on muscle viscoelastic properties of well-trained male athletes
Author
Ho, Yieng Yieng
Supervisor
Kong, Pui Wah
Abstract
Skeletal muscles serve primarily as force generators to produce movement, maintain posture, stabilise joints and generate heat. The ability of muscles to dissipate the mechanical energy of external impact and unload the joints is also essential in physical activities. In this study, myotonometry was used to assess the acute effect of downhill running on the muscle viscoelastic properties.
Six well-trained male athletes, aged between 22 and 27 years old, were recruited for this within-subject study. They were tasked to run downhill at a gradient of 10º for 40 minutes on a treadmill at a speed equivalent to 80% of the maximal heart rate achieved during level running. Muscle tone, stiffness and elasticity of rectus femoris, biceps femoris, ibialis anterior and gastrocnemius medialis of both the lower limbs of each subject were measured using the MyotonPRO.
Between-day reliability of the MyotonPRO was assessed using mean coefficient of variation (muscle tone, CV < 2.6%; stiffness, CV < 3.5 %; elasticity, CV < 6.8%) and the Wilcoxon signed rank-test was performed on three dependent variables for each muscle to detect the acute effect of downhill running on the stiffness, decrement and muscle tone of each muscle. Statistical significance was set at p < .05. Differences were also considered practically meaningful if the effect size was large (r ≥ .5). The findings revealed that the MyotonPRO was reliable in monitoring muscle viscoelastic properties between days. The lower leg muscles, tibialis anterior and gastrocnemius medialis, seemed more sensitive than the thigh muscles to downhill running. An increase in muscle stiffness and tone of both the tibialis anterior (2.4% ) and gastrocnemius medialis (4.1%) were observed post-exercise. On the contrary, a decrease in the muscle stiffness of rectus femoris (-1.9%) and elasticity of tibialis anterior (-3.7%) were detected.
The findings of this experiment may not be directly applicable to prevent injury. However, it does show the potential of the MyotonPRO being used as a tool to monitor training demand to ensure sufficient rest between training bouts. Over time, results of the usage of MyotonPRO can be collected to build a database. These data can be further segmentized and categorized to create a meaningful reference point for practitioners to interpret results of the tool and its significance accordingly. This, in turn, might potentially reduce the occurrence of overuse injuries.
Six well-trained male athletes, aged between 22 and 27 years old, were recruited for this within-subject study. They were tasked to run downhill at a gradient of 10º for 40 minutes on a treadmill at a speed equivalent to 80% of the maximal heart rate achieved during level running. Muscle tone, stiffness and elasticity of rectus femoris, biceps femoris, ibialis anterior and gastrocnemius medialis of both the lower limbs of each subject were measured using the MyotonPRO.
Between-day reliability of the MyotonPRO was assessed using mean coefficient of variation (muscle tone, CV < 2.6%; stiffness, CV < 3.5 %; elasticity, CV < 6.8%) and the Wilcoxon signed rank-test was performed on three dependent variables for each muscle to detect the acute effect of downhill running on the stiffness, decrement and muscle tone of each muscle. Statistical significance was set at p < .05. Differences were also considered practically meaningful if the effect size was large (r ≥ .5). The findings revealed that the MyotonPRO was reliable in monitoring muscle viscoelastic properties between days. The lower leg muscles, tibialis anterior and gastrocnemius medialis, seemed more sensitive than the thigh muscles to downhill running. An increase in muscle stiffness and tone of both the tibialis anterior (2.4% ) and gastrocnemius medialis (4.1%) were observed post-exercise. On the contrary, a decrease in the muscle stiffness of rectus femoris (-1.9%) and elasticity of tibialis anterior (-3.7%) were detected.
The findings of this experiment may not be directly applicable to prevent injury. However, it does show the potential of the MyotonPRO being used as a tool to monitor training demand to ensure sufficient rest between training bouts. Over time, results of the usage of MyotonPRO can be collected to build a database. These data can be further segmentized and categorized to create a meaningful reference point for practitioners to interpret results of the tool and its significance accordingly. This, in turn, might potentially reduce the occurrence of overuse injuries.
Date Issued
2016
Call Number
QM165 Ho
Date Submitted
2016