WPI Fights Strength Declines After Muscle Damage

MELBOURNE, AustraliaConsuming whey protein during resistance exercise may help the body recover from the damage to the skeletal muscles, according to a new study (J Intl Soc Sports Nutr. 2010;7:30. DOI: 10.1186/1550-2783-7-30). Researchers from Victoria University and the University of Queensland noted dietary proteins play an important role in regulating protein metabolism in muscle, with WPI particularly effective at increasing blood amino acids and protein synthesis. The team therefore sought to determine whether ingestion of a WPI product could accelerate muscle strength recovery after exercise-induced muscle damage.

Untrained men (n=17, ages 18-28) were randomized into two groups: WPI or carbohydrate (CHO). The 14-day intervention featured a unilateral eccentric contraction-based resistance exercise session on the leg press, leg extension and leg flexion machines. Participants consumed 1.5 g/kg body weight/d of the supplement, in five periods: ~30 g immediately after exercise, and the rest divided between breakfast, lunch, afternoon and after evening meal. Blood markers of muscle damage were plasma creatine kinase and lactate dehydrogenase (LDH) levels. Muscle strength was examined by voluntary isokinetic knee extension.

The subjects consuming WPI had significantly higher isometric knee extension strength at both three days and seven days into recovery from the active exercise intervention period compared to those who had taken CHO. There were strong tendencies for higher isokinetic forces (extension and flexion) in the WPI group as well after seven days recovery. Further, plasma levels of LDH tended to be lower in the WPI group during recovery. Researchers concluded whey protein isolate supplementation could prevent the impairment in muscle strength during recovery from resistance exercise.