In the previous blog, I discussed results from a session I chaired at the ECOSEP conference in Barcelona. Professors Kevin Tipton from the University of Stirling in Scotland and Stuart Phillips from McMaster University in Canada discussed recovery from muscle injury. I summarised the nutrition recommendations for muscle injury here. Keith Baar from the University of California at Davis then continued to discuss the tendon, which is much less researched than muscle.
Building injury resistant or "fast" tendons
Tendon injuries are very common and one of the reasons for this high rate of injury is that strength, power, and speed are dependent on stiff connective tissues (tendon, ligaments). Stiffer tendons may be better for performance but they are also more injury prone. It is possible to make tendons stiffer through plyometrics and this can help speed, strength and power, but stiffer connective tissues can contribute to higher rates of injury to the attached musculature. The stiffness of a connective tissue, like a tendon or ligament, is dependent on two main factors:
the collagen content
the amount of crosslinks within the collagen.
Crosslinks increase when athletes train at a high speed or with rapid changes in direction.
Crosslinks decrease when using strength exercise with slow movements. Increasing slow contractions are optimal for improving tendon health and incorporating slow contractions into a rehab program can decrease time away from sport (return to play).
Check out this blog about the extracellular matrix (ECM) where Keith Baar discusses this topic in a little more detail.
Rehab and nutrition
Unlike muscle, connective tissue cells adapt quickly to exercise. To get maximal effects you only need 5-10 minutes of activity. You then have to wait another 6 hours before the tissue becomes responsive again. Keith showed an example of a rehab program of a major league baseball player who recovered well by exercising 10 min 3 times per day with 6 hours in between sessions. Keith also presented anecdotal evidence that eating gelatin and vitamin C may promote greater collagen production, especially following a tendon/ligament rupture. (5g gelatin, 500mg vitamin, 30-60min before exercise).
Unlike muscle, connective tissue cells adapt quickly to exercise.
Apart from these specific exercise and feeding regimes, the recommendations for protein intake are similar to those in muscle:
20g of high quality protein (0.3 g/kg/meal) at EVERY meal
Protein intake around rehab sessions
With inactivity tendons lose their compliance
Keith also warned that following forced inactivity the tendons lose their compliance near the muscle end. This may actually make players who return from injury slightly faster but it makes the muscle much more prone to injury. It is important therefore to monitor and manage the training load.
All in all, we can distill some great practical guidelines from the evidence we currently have, but there is a long way to go still until we fully understand the processes that promote repair after injury and thus we can expect changes and improvements in the recommendations in the next few years.