Comparison of the effects of hold relax and pelvic resistive exercise on the range of motion of the knee joints in normal young volunteers

持続伸張手技(SS)やホールド・リラックス手技(HR)・骨盤の後方下制の中間域での静止性収縮手技(SCPD)の施行時間の違いが他動及び自動関節可動域(PROM・AROM)に及ぼす効果の差異について検証した.対象は健常者66名(男性36名,女性30名,平均年齢(SD)21.4.(0.5)歳) である.66名を無作為に手技はSS,HR,SCPDを,施行時間は20秒あるいは40秒を行う6つに分類し, 他動と自動の膝関節伸展の測定を行った.手技と施行時間と測定方法を要因とした三元配置分散分析の結果,手技,施行時間と測定方法間に有意差が認められた(p＜0.05).多重比較検定 (Tukey法) の結果,SSよりHRとSCPDにおいて有意な増大が認められ(p＜0.01),20秒の施行時間ではAROMよりPROMにおいて,AROMの測定方法では20秒より40秒において有意な増大が認められた(p＜0.05). PROM改善のためには収縮時間を長くしてもハムストリングスへの抑制効果が大きくなる可能性が少ないことが示唆されたが,AROMの増大には、収縮時間が長い方が膝伸筋群への促通効果があることが示唆された.Background: Facilitation by a resistive static contraction (SCF) using a Proprioceptive Neuromuscular Facilitation (PNF) pattern in mid-range pelvic posterior elevation (SCPD) and a hold relax (HR) technique utilizing a shortening contraction of the hamstrings to place the hamstrings on stretch followed by a static contraction of the hamstrings has been shown to induce significant improvement in the active range of motion (AROM) of knee extension as compared to a sustained stretching (SS) of the hamstrings for 20 seconds. However, the degrees of improvement in AROM or passive range of motion (PROM) obtained by an interaction of methods and contraction duration (CD) of the SCPD and HR techniques has not been clarified. Aim: The purpose of this study was to determine the immediate effects of a combination of different techniques (SCPD, HR, and SS) and different CDs (20 and 40 seconds) on the improvement of PROM and AROM of knee extension through the lengthening of the hamstrings in normal young volunteers. Method: Sixty-six college students, with a mean age (SD) of 21.4 (0.5) years, were randomly assigned to one of six groups (combination of techniques and CDs (3×2)) . Both PROM and AROM were randomly measured between and after each technique and CD combination. Results: The results of a three-way ANOVA showed significant differences between the three techniques, interaction between two methods, and CDs. SCPD and HR showed significant improvements as compared to SS. The 20-second CD showed a significantly larger improvement in PROM than the 40-second CD improvement in AROM. The 40-second CD showed a larger improvement in AROM than the 20-second CD improvement in AROM. Conclusion: Although it may not be effective to increase the CD to improve PROM, it may be effective to improve AROM by increasing the CD