Conclusion Overall , our findings do not support the presence of a secondary loss of strength following an acute muscle injury , and strongly suggest that strength , on average , recovers steadily over the first 3 days post-injury
Background An immediate loss of strength follows virtually all types of muscle injury but there is debate whether the initial strength loss is maximal or if a secondary loss of strength occurs during the first 3 days post-injury .
Objective The objective of this analysis was to conduct a systematic review and meta- analysis of the research literature to determine if a secondary loss of strength occurs after an injurious initiating event .
Damage to the human quadriceps muscle from eccentric exercise and the training effect.
Nine participants performed two bouts of a step exercise , during which the quadriceps muscle of one leg acted eccentrically . Before and after the exercise , isokinetic torque was measured over a range of knee angles to determine the optimum angle for torque . Immediately after the first bout of exercise , the quadriceps showed a significant ( P < 0.05 ) shift of 15.6 + /- 1.4 degrees ( mean + /-sx ) of its optimum angle in the direction of longer lengths , suggesting the presence of damage . A drop in peak torque , together with delayed soreness and swelling , confirmed that damage to muscle fibres had occurred . After the second bout of exercise , 8 days later , the shift in optimum angle was 10.4 + /- 1.0 degrees , which was significantly less than after the first bout ( P < 0.05 ) . Other indicators of damage were also reduced . In addition , the muscle exhibited a sustained shift in optimum angle ( 3.4 + /- 0.9 degrees ) , suggesting that some adaptation had taken place after the first bout of exercise . We conclude that muscles like the quadriceps can show evidence of damage after a specific programme of eccentric exercise , followed by an adaptation response . This is despite the fact that the quadriceps routinely undergoes eccentric contractions in everyday activities
Conclusion Overall , our findings do not support the presence of a secondary loss of strength following an acute muscle injury , and strongly suggest that strength , on average , recovers steadily over the first 3 days post-injury
Background An immediate loss of strength follows virtually all types of muscle injury but there is debate whether the initial strength loss is maximal or if a secondary loss of strength occurs during the first 3 days post-injury .
Objective The objective of this analysis was to conduct a systematic review and meta- analysis of the research literature to determine if a secondary loss of strength occurs after an injurious initiating event .