Intermittently increased repetitive work intensity and neuromuscular function in the cold.
This study evaluated whether cold-induced deterioration in neuromuscular function can be restored by intermittently increasing the workload. We examined the level of muscular strain, agonist-antagonist co-activation, the occurrence of EMG gaps and neuromuscular efficiency in wrist flexor and extensor muscles at 21°C (TN) and 4°C (C(10)) with a 10%MVC workload. During second exposure to 4°C (C(50)) the workload was increased every fourth minute to 50%MVC. The results indicated that muscular strain and co-activation was the highest and the amount of EMG gaps and neuromuscular efficiency the lowest at C(10). By intermittently increasing the workload at C(50) we were able to reduce muscular strain and co-activation (p<0.05) and induce a trend like increase in EMG gaps and enhance neuromuscular efficiency in relation to C(10) (NS). It may be concluded that intermittently increasing the workload, i.e. breaking the monotonous work cycle was able to partially restore neuromuscular function.
Finnish Institute of Occupational Health, Finland. juha.oksa@ttl.fi
Juha
J
Oksa
Soile
S
Paasovaara
Tommi
T
Ollila
D000328:Adult; D003080:Cold Temperature / Q000009:adverse effects*; D004576:Electromyography; D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000503:physiopathology*; D017933:Peripheral Nervous System / Q000503:physiopathology*; D016526:Workload; D014953:Wrist / Q000294:innervation / Q000502:physiology; D055815:Young Adult