Running is unique in that each step involves the absorption and transmission of body weight. This causes stress on bones, tendons and ligaments and is the reason you’ll wake up with aching joints or soreness the morning after a hard effort. But as science suggests, there’s a fine line between a stress reaction and healthy adaptation. According to a 2006 study, 9 of 21 collegiate runners measured had asymptomatic tibial stress reactions on MRI, with no direct correlation to subsequent clinical outcomes. In short, the constant force absorption of running had created a background stressor not he bone that made it bounce back stronger for those athletes. But where exactly do you draw the line, as it could easily have also amounted to a more serious stress fracture that proved debilitating. The answer lies in consistent training. Through consistent efforts, low-level stress actually helps the body manage these adaptation processes without needing time-off or a visit to the physiotherapist.
Muscle fibre growth is actually enhanced by consistent stress and recovery cycles and given the amount of stress the body transmits with each stride while running, you don’t need to be out pounding the pavement for hours to see healthy adaptation. If you have the choice of doing an hour run three times per week, or a thirty minute run six times per week, the second option not only sees you get fitter and healthier, but will also see you improve speed and endurance.
It can be easy to fall into the trap of thinking if some is good, more is always better. But those who want to see longevity in a sport would do well to avoid this. You might not be able to get in a long workout or run, but if you can get in something - 10 minutes, 20 minutes or 30 - it’s always better than nothing, and your body will thank you for it down the line.