A study by Dr. Vonda Wright at the UPMC Center for Sportsmedicine in Pittsburgh assessed the fitness and strength of recreational masters runners, cyclists and swimmers. Her subjects ranged in age from 40 to 81. Dr. Wright used MRI scans of the upper leg to measure muscle and fat content. She found no significant decline in muscle size or strength due to aging. The MRIs of the quadriceps of her 40 year old and 70 year old subjects were virtually identical. In comparison, MRI scans of a sedentary 70 year old’s quad show a shrunken muscle covered in fat.
Research at the Canadian Centre for Activity and Aging at the University of Western Ontario found that the leg muscles of runners in their 60’s and 20’s contained the same number of motor units (the reduction of motor units is considered to be a key contributor to age-related muscle loss). In comparison, non-runners in their 60’s exhibited a 35% decline in the number of motor units vs. subjects who were in their 20’s.
A previous Feature Article that appeared in our newsletter You’re Not Getting Older You’re Getting Faster reported on research that concluded that running economy does not decline with age. The higher your running economy, the less oxygen you require to run at a given pace. Therefore, an “economical” runner can continue running at a given speed for a longer period of time than her less economical counterpart. Running economy is reliable indicator of distance race performance.
These research findings are great news! Being able to utilize oxygen efficiently and possessing well preserved muscle strength, middle aged and older runners are capable of fast running and race times.
The same article reported that runners age 40+ are more prone to Achilles, hamstrings and calf injuries than younger runners. “The normal wear and tear that occurs with training seems to take greater time to repair with aging, and older runners continue running at a frequency similar to that of younger runners.”
The study supports our experience that following a training regimen that does not take age into account and allow for adequate recovery time is a leading contributor to injuries among middle aged and older runners.
A followup study at the University of Western Ontario examined the arms muscles of runners in their 60’s and their sedentary counterparts. The study found that the arms of both contained much fewer motor units than the subjects who were in their 20’s.