過去許多研究指出，關節間的主動肌(agonist)和拮抗肌(antagonist)肌群問之肌力或肌耐力的不平衡是造成運動傷害的可能原因；當運動時，肌肉不會只有單一向心收縮的型態，而是反覆的以離心(eccentric contraction)與向心(concentric contraction)收縮的方式在運作；因此本篇之目的，探討長短跑選手之向心與離心之腿後肌與股四頭肌比值(H/Q ratio)與最大肌力，是否會因為其運動型態的差異，而有所不同；本研究使用Biodex System III測試30名選手在角速度在每秒60度與300度之等速肌力值，以獨立樣本t考驗與單因子變異數分析之；結果顯示長跑選手在300度/秒向心測試中H/Q比值高於短跑選手，而短跑選手之腿後肌與股四頭肌肌力值，比長跑選手要來的大，顯示爆發力型項目在肌力的表現值較高，不過在左右兩側與性別上皆沒有差異；一般說來，國內訓練多注重向心肌力，在離心肌力上較缺乏訓練，因此提供腿後肌離心肌力與股四頭肌向心肌力比值(Hecc/Qcon. ratio, DCR)，為一功能性之肌力平衡參考依據，以降低選手腿後肌肌肉拉傷之機率，讓運動員更加提高其運動表現。

Several studies have indicated that imbalance between agonist and antagonist of a joint is one of the reasons to cause muscular injury. The contraction of muscles was not only one concentric type when exercising, usually contracted reiteratively in eccentric and concentric types. Thus, the main purposing of this study was to evaluate the isokinetic strength of hamstrings and quadriceps in 30 sprinters and long-distance runners. Two speeds of 60/s and 300/s were used to investigate subjects' isokinetic strengths by Biodex System III dynamometer. The results were analyzed with the independents t test and the one-way ANOVA. The results showed that the H/Q concentric strength ratios of the long-distance runners were higher than the ratios of the sprinters. However, with a more functional way of comparison, the strength ratio of eccentric peak torque of hamstrings and concentric peak torque of quadriceps of sprinters was higher than that in the long-distance runners. This is a good indication when evaluating H/Q ratios of athletes that functional motion and muscle contraction type should be considered. The results also showed no significant difference in the ratios between both sides of the extremity and genders. This study showed that the Hec/Qcon (Dynamic Control Ratio) played a meaningful clinical reference when treating quadriceps and hamstrings injuries.