[PP-3-2] ポスター：基礎研究 3Characteristics of Hand-intrinsic Muscle Activities and Grip Force Control During Precision Grips
Introduction
The aim of this study was to investigate the characteristics of hand-intrinsic muscles and the grip force (GF) control in three different pinch types.
Methods
Six healthy young adults (four females and two males, 21.97 ± 0.54 years) participated in this study. All participants performed a grip and lift task by randomly using three different pinch types (pulp pinch, tip pinch, and lateral pinch). GF control was evaluated using two kinetic parameters: the mean GF and the center of pressure (COP) trajectory. We monitored individual finger GF (N) and COP (mm) using two pressure sensors with a high spatial resolution during the first five seconds in the grip and lift task. Moreover, we measured the muscle electrical activity of the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles using surface electromyography (EMG) during the fifth and the tenth seconds of the holding phase. Also, the ratio of FDI to APB muscle was calculated to investigate the muscle coordination. In a clinical test, the pinch strengths were measured in three pinch types. All experiment and measurement were conducted using dominant hand.
Results
Participants exerted the greatest GF in tip pinch on both thumb (1242.28 ± 409.18 N) and index finger (1012.45 ± 271.80 N). Interestingly, tip pinch produced the smallest COP trajectory from the thumb (23.30 ± 6.67 mm) and the index finger (19.27 ± 5.59 mm). The amount of muscle activity of APB (pulp pinch; 0.18 ± 0.15 mV, tip pinch; 0.12 ± 0.09 mV, and lateral pinch; 0.10 ± 0.10 mV) was greater than that of FDI (0.02 ± 0.01 mV) in three different pinch types. Moreover, the ratio of FDI to ABP was significant difference only between pulp (13.45 ± 9.22 %) and lateral pinch (37.54 ± 21.68 %).
Conclusions
Our findings suggested that different pinch type influences GF and COP trajectory in grip and lift task. In addition, the fact that the amount of muscle activity of the thumb reached the greatest value in pulp pinch indicates the optimization of this pinch type for the thumb movement compared with tip and lateral pinch.
The aim of this study was to investigate the characteristics of hand-intrinsic muscles and the grip force (GF) control in three different pinch types.
Methods
Six healthy young adults (four females and two males, 21.97 ± 0.54 years) participated in this study. All participants performed a grip and lift task by randomly using three different pinch types (pulp pinch, tip pinch, and lateral pinch). GF control was evaluated using two kinetic parameters: the mean GF and the center of pressure (COP) trajectory. We monitored individual finger GF (N) and COP (mm) using two pressure sensors with a high spatial resolution during the first five seconds in the grip and lift task. Moreover, we measured the muscle electrical activity of the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles using surface electromyography (EMG) during the fifth and the tenth seconds of the holding phase. Also, the ratio of FDI to APB muscle was calculated to investigate the muscle coordination. In a clinical test, the pinch strengths were measured in three pinch types. All experiment and measurement were conducted using dominant hand.
Results
Participants exerted the greatest GF in tip pinch on both thumb (1242.28 ± 409.18 N) and index finger (1012.45 ± 271.80 N). Interestingly, tip pinch produced the smallest COP trajectory from the thumb (23.30 ± 6.67 mm) and the index finger (19.27 ± 5.59 mm). The amount of muscle activity of APB (pulp pinch; 0.18 ± 0.15 mV, tip pinch; 0.12 ± 0.09 mV, and lateral pinch; 0.10 ± 0.10 mV) was greater than that of FDI (0.02 ± 0.01 mV) in three different pinch types. Moreover, the ratio of FDI to ABP was significant difference only between pulp (13.45 ± 9.22 %) and lateral pinch (37.54 ± 21.68 %).
Conclusions
Our findings suggested that different pinch type influences GF and COP trajectory in grip and lift task. In addition, the fact that the amount of muscle activity of the thumb reached the greatest value in pulp pinch indicates the optimization of this pinch type for the thumb movement compared with tip and lateral pinch.