The effect of cooling on muscle fatigue and recovery

The aim of the study undertaken was to establish the effect of cooling on fatigue of the skeletal muscle and recovery after undergoing physical load of different modes by humans. Methods: Muscle temperature measuring, electrical stimulation, isometric, isokinetic, eccentric-concentric load, evaluation of creatine kinase, leg immersion in cold water, mathematical statistics. Conclustions: after decreasing muscle temperature by 6.21.5o C its function changes considerably: a) there occurs a decrease in voluntary contraction force and capacity; b) involuntary contraction force evoked by low (20 Hz), high (50 Hz) and extremely high (100 Hz) stimulation frequencies decreases irrespective of muscle length; c) involuntary contraction force evoked by extremely low (10 Hz) stimulation frequencies increases irrespective of muscle length; d) involuntary muscle contraction and relaxation time increases irrespective of both stimulation frequency and muscle length. Cooling accompanied by repeated stimulation of the muscle with electrical impulses of high frequency worsens the functional properties of the muscle but increases the resistance of muscle contraction force to fatigue. Cooling after eccentric–concentric physical loads accelerates muscle recovery and has effect on the secondary indices of muscle damage: a) there is a decrease in creatine kinase activity and muscle pain; b) there occurs a faster recovery of muscle voluntary and involuntary contraction force and it does not depend either on stimulation frequency or muscle length. Cooling after concentric (isokinetic) physical load of maximum intensity has no significant effect either on the recovery of maximum voluntary force of the muscle or disappearance of fatigue caused by stimulation at low frequencies but involuntary force of cooled muscle evoked by stimulation at low (20 Hz), high (50 Hz) and extremely high (100 Hz) frequencies recovers much faster