| Autor: |
Colosio M; Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.; Department of Molecular Medicine, University of Pavia, Pavia, Italy., Rasica L; Institute of Biomedical Technologies, National Research Council, Segrate, Italy.; Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada., Baldassarre G; Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.; Institute of Biomedical Technologies, National Research Council, Segrate, Italy., Temesi J; Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom., Vernillo G; Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy., Marzorati M; Institute of Biomedical Technologies, National Research Council, Segrate, Italy., Porcelli S; Institute of Biomedical Technologies, National Research Council, Segrate, Italy.; Department of Molecular Medicine, University of Pavia, Pavia, Italy. |
| Abstrakt: |
Elbow flexors (EFs) and knee extensors (KEs) have shown differences in performance fatigability and recovery of neuromuscular function after isometric and isotonic single-joint fatiguing contractions. However, dynamic multi-joint movements are more representative of real-world activities. The aim of the study was to assess central and peripheral mechanisms of fatigability after either arm-cranking or cycling. Ten physically active men performed maximal incremental arm-cranking and cycling until task failure. Maximal voluntary isometric contraction (MVIC) and electrically evoked forces of both EF and KE were assessed before (PRE) and 1 (POST) and 20 (POST20) min after exercise. At POST, MVIC decreased similarly to 76 ± 8% and 81 ± 7% (both P < 0.001) of PRE for EF and KE, respectively. MVIC force remained lower than PRE at POST20 for both EF and KE (85 ± 8% vs. 95 ± 3% of PRE, P ≤ 0.033), having recovered less in EF than in KE ( P = 0.003). Electrically evoked forces decreased similarly from PRE to POST in EF and KE (all P > 0.05). At POST20, the ratio of low-to-high frequency doublets was lower in EF than in KE (75 ± 13% vs. 85 ± 10% of PRE; P ≤ 0.034). Dynamic maximal incremental exercise acutely induced similar magnitudes of MVIC and evoked force loss in EF and KE. However, at POST20, impaired MVIC recovery and lower ratio of low-to-high frequency doublets in EF than in KE suggest the recovery of neuromuscular function after dynamic maximal exercises is specific to and dependent on changes within the muscles investigated. |
