Kuo L C, Chang J H, Lin C F, Hsu H Y, Ho K Y, Su F C
Department of Occupational Therapy, National Cheng Kung University, Tainan, Taiwan, Republic of China.
Proc Inst Mech Eng H. 2009 Jul;223(5):577-88. doi: 10.1243/09544119JEIM504.
This study discusses the force-generating capacity of thumb muscles during jar-opening tasks using two grip patterns: the power grip and the precision grip. This study develops a three-dimensional biomechanical model of the thumb to predict muscle forces in jar-opening activities based on external forces measured by a custom-designed jar device. Ten healthy subjects participated in the study. Each participant turned a jar lid of 66 mm diameter counterclockwise with maximal effort and preferred speed using both grip patterns. The average normal and tangential forces applied by the thumb to the jar lid show that the normal force is the primary contributive force for opening a jar. This normal force is approximately three times the tangential force. Muscular force-generating capacity measurements show that the major active muscles during a jar-opening activity for both grips include the flexor pollicis longus, flexor pollicis brevis, abductor pollicis brevis, adductor pollicis, and opponens pollicis. The total muscle force ratios for the precision grip and power grip with respect to externally applied forces are 5.6 and 4.7 respectively. These ratios indicate that the power grip pattern produces less muscle force per unit of external applied load. The technique proposed in this study provides a proper apparatus and model for measuring three-dimensional loads and estimating the force-generating capacity of each muscle and tendon of the thumb during jar-opening tasks.
本研究探讨了在拧开罐子任务中，使用两种握持方式（强力握持和精确握持）时拇指肌肉的发力能力。本研究建立了一个拇指的三维生物力学模型，以根据定制设计的罐子装置测量的外力来预测拧开罐子活动中的肌肉力量。十名健康受试者参与了该研究。每位受试者使用两种握持方式，以最大努力和偏好的速度逆时针转动直径为66毫米的罐子盖子。拇指施加在罐子盖子上的平均法向力和切向力表明，法向力是打开罐子的主要作用力。该法向力约为切向力的三倍。肌肉发力能力测量结果表明，两种握持方式在拧开罐子活动中的主要活跃肌肉包括拇长屈肌、拇短屈肌、拇短展肌、拇收肌和拇对掌肌。精确握持和强力握持相对于外部施加力的总肌肉力比分别为5.6和4.7。这些比率表明，强力握持方式每单位外部施加负荷产生的肌肉力较小。本研究中提出的技术为测量三维负荷以及估计拧开罐子任务中拇指各肌肉和肌腱的发力能力提供了合适的仪器和模型。
