title: Effects of the resting time associated with the number of trials on the total and individual finger forces in a maximum grasping task.
abstract: The repetitive and excessive workload accompanying grip strength- or hand-intensive tasks are often considered to be common causes of work-related upper limb musculoskeletal disorders. For this reason, numerous experimental studies have been performed on maximum grip strength. However, due to an absence of standard guidelines, researchers have adopted different resting times and number of trials suited for their particular research purposes. The effects of resting time and the number of trials on the maximum total grip strength and individual finger forces of 24 participants over 20 trials were investigated. Results showed that the total grip strength and individual finger strengths differed significantly according to the resting time and the number of trials (p<0.05). Overall, grip strength tended to increase with a reduction in resting time (% reduction: 7.8%, 9.1%, 11.1%, and 13.0% for 3 min, 2 min, 1 min, and 30s resting time, respectively) as well as with an increase in the number of trials (% reduction: 8%, 10%, 13%, and 16% for 5th, 10th, 15th, and 20th trials). The effects of resting time and the number of trials also showed statistically significant effects on individual finger forces. Regression equations of total grip strength and finger forces with resting time and number of trials were established. These equations were then applied to formulate guidelines for appropriate resting times in experiments based on the number of trials and acceptable reductions in grip strength. Data from this and future studies regarding decreasing grip strength and the contribution of each finger are expected to form the groundwork for ergonomic hand tool design and development.
authors.affiliation: Department of Industrial Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Cheol-Min
authors.initials: CM
authors.lastname: Lim
authors.affiliation: Department of Industrial Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea. Electronic address: ykong@skku.edu.
authors.forename: Yong-Ku
authors.initials: YK
authors.lastname: Kong
mesh_terms: D005385:Fingers / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D012146:Rest; D013997:Time Factors; D055815:Young Adult
keywords: Maximum gripping task; Resting time; Trial