Acute effect of heel-drop exercise with varying ranges of motion on the gastrocnemius aponeurosis-tendon's mechanical properties.
The objectives of this study was to investigate the acute effects of various magnitudes of tendon strain on the mechanical properties of the human medial gastrocnemius (MG) in vivo during controlled heel-drop exercises. Seven male and seven female volunteers performed two different exercises executed one month apart: one was a heel-drop exercise on a block (HDB), and the other was a heel-drop exercise on level floor (HDL). In each regimen, the subjects completed a session of 150 heel-drop exercises (15 repetitions×10 sets; with a 30 s rest following each set). Before and immediately after the heel-drop exercise, the ankle plantar flexor torque and elongation of the MG were measured using a combined measurement system of dynamometry and ultrasonography and then the MG tendon strain and stiffness were evaluated in each subject. The tendon stiffness measured prior to the exercises was not significantly different between the two groups 23.7±10.6N/mm and 24.1±10.0N/mm for the HDB and HDL, respectively (p>.05). During the heel-drop exercise, it was found that the tendon strain during the heel-drop exercise on a block (8.4±3.7%) was significantly higher than the strain measured on the level floor (5.4±3.8%) (p<.05). In addition, the tendon stiffness following the heel-drop exercise on a block (32.3±12.2N/mm) was significantly greater than the tendon stiffness measured following the heel-drop exercise on the level floor (25.4±11.4N/mm) (p<.05). The results of this study suggest that tendon stiffness immediately following a heel-drop exercise depends on the magnitude of tendon strain.
Department of Physical Education, College of Sciences in Education, Yonsei University, Seoul, Republic of Korea.
Siwoo
S
Jeong
Department of Silver Industrial Engineering, College of Future Human Resource Development, Kangnam University, Yongin, Republic of Korea.
Dae-Yeon
DY
Lee
Department of Physical Education, College of Sciences in Education, Yonsei University, Seoul, Republic of Korea.
Dong-Sung
DS
Choi
Department of Physical Education, College of Sciences in Education, Yonsei University, Seoul, Republic of Korea. Electronic address: xbridge1997@yonsei.ac.kr.
Hae-Dong
HD
Lee
D000125:Achilles Tendon / Q000502:physiology*; D000222:Adaptation, Physiological; D000328:Adult; D000704:Analysis of Variance; D000842:Ankle / Q000502:physiology; D004548:Elasticity; D015444:Exercise / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006365:Heel / Q000502:physiology*; D006801:Humans; D008297:Male; D009038:Motion; D018482:Muscle, Skeletal / Q000502:physiology*; D013314:Stress, Mechanical; D019415:Torque; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
In vivo; Tendon stiffness; Tendon strain magnitude; Ultrasonography