The answer to the first question comes from the recent study by Ekstrand et al (2011) which has showed that muscle injuries incidence increases with age. In this study, professional players were placed in 3 age categories (16-21 yrs, 22-30 yrs & >30 yrs). The analysis showed 35% greater incidence for muscle injury in training in players aged below 22 years old compared with aged >30 years old. No difference was observed between the intermediate groups. During a match, young players had a significantly lower incidence compared with the other 2 categories. These results suggest that the incidence of muscle injury increases with age in professional players.
The next question is: is this associated with a delayed recovery rate with age? There is a limited number of studies on this issue and these are not in football players but athletes in extreme sports (mountain running). One study has shown that recovery rate is slower with age (Easthope et al., 2010). In another study, recovery rate was similar in young and non-young runners after a long race (Nassis et al., unpublished data). In the latter study, athletes in the 2 age-groups had similar training history and thus any difference could be attributed to the biological process of recovery. It seems, therefore, that recovery rate might not be different with age when athletes are of similar training level. More data are needed specific on football players.
Easthope et al. European Journal of Applied Physiology 110: 1107-1116, 2010.
Ekstrand et al. American Journal of Sports Medicine, 39 (6): 1226-32, 2011.
Nassis et al. under review