The Influence of the Improvement of Calf Strength on Barefoot Loading

The purpose of this study was to determine whether enhancement of calf muscular strength can produce influence on plantar pressure in barefoot running. Ten healthy male subjects (age:22±2.5 years, height: 1.76±0.4m, body mass: 65±2.5kg) participate this experiment enduring 8-week strength training adopting by calf raise movement on calf muscle. A medical ultrasonic instrument (Q6, China) was used to observe the variation of calf muscular morphology. A plantar pressure plate ( Novel Emed, Germany) was used to collect the variation of 8-region plantar pressure. After 8-week strength training, a significant increasing trend between pre-and post-strength training in subject`s pinnation angle (PA) of the gastrocnemius was found. Under strength training, there are some significant variations between pre-and post-plantar pressure. The start point of center of pressure (COP) gradually forward (middle foot 80%, forefoot 20%); the peak pressure of subject`s heel foot (HF) significantly lower; the maximal force in second-third metatarsal (M 2-3), medial foot (MF) and HF significantly decrease; the contact area in other toe (OT) significantly increase as well as MF and HF significantly decrease; the time-force integral in M2-3 and HF significantly lower and in MF significantly enhance. These results suggest, the enhancement of calf muscular strength may produce positively influence on beginning transitional process from shod running to barefoot running and is also worth to as a feasible way to recommend. However, the effects of strength straining on plantar pressure do not fully explore and still need to deeply explore own to existing limitations.