Contractile Properties of Single Muscle Fiber and Their Relations to Whole Muscle Strength in Korean Young Male

Yu-Nah Jeon, Hee-Jaeng Kim, So-Young Yang, So-Hyun Lee, Dae-Young Kim, Jun-Hyun Bae, Ho-Jun Lee, Jae-Young Lim, Seung-Jun Choi
2018 Exercise Science  
PURPOSE: This study investigated the muscle fiber type-related contractile properties and examined the relationship between whole limb muscle strengths and single muscle fiber contractile properties in Korean men. METHODS: Six Korean men (29.8±1.49 yr) were recruited and participated in the study. Samples were obtained from vastus lateralis muscles. CSA, Po, SF, Vo of single fiber segments were measured using an isometric force transducer and a high-speed motor. Silver staining was performed to
more » ... ng was performed to identify MHC isoform composition of single muscle fiber segments. Multiple regression was tested to identify the relationship between single muscle fiber contractile properties and whole muscle strength. RESULTS: MHC isoforms were distributed in different proportion (Type I: 57.3%, IIa: 34.2%, IIa/IIx: 4.3%, IIx: 4.3%). CSA of type IIx were smaller compared to type I (-50%) and type IIa (-57.5%). Po in type IIa was 12.9% higher compared to type I (p<.05). While SF in type IIa were 7.7% higher than type I, type IIx were higher than type I, IIa, IIa/IIx (31.4%, 25.7%, 30.9%). Vo increased in the order type I<IIa<IIa/IIx<IIx. There was positive correlation between single fiber and properties (Po vs. thigh strength: r 2 =.248, Po vs. thigh power: r 2 =.058, Vo vs. thigh power: r 2 =.095). CONCLUSIONS: These results suggest that single muscle fiber contractile properties were exclusively dependent on fiber type isoforms, ruling out a possibility of race-induced difference in fiber type-matched contractile properties. 인간의 골격근은 자세를 유지하고 일상생활을 수행하기 위한 기능 적인 힘을 발휘하는 중요한 조직이며, 힘(force)과 파워(power)를 발생 시킴으로써 건강을 유지하고 독립적인 생활을 가능하게 한다. 이러한 기능을 하는 골격근의 수준을 분석하기 위한 방법은 전근(whole muscle)에서 근세포(myocyte) 또는 분자(molecular) 수준에 이르기까지 다 양한 수준에서 이루어져 왔다[1]. 전근의 힘과 파워는 악력 측정(hand grip strength measurement), 최 대자발성수축(maximum voluntary isometric contraction) 그리고 등속
doi:10.15857/ksep.2018.27.1.23 fatcat:apyuiyvsu5bzragiegt2rtuztq