Preventing Tendon Injuries in Explosive Athletes

Per Aagaard of the Danish Institute of Sports Sciences and Clinical Biomechanics recently lectured at the High Performance Centre in Perry Barr, Birmingham.

I had the good fortune of being invited by Neil Black, the Head of Sports Science and Medicine for UK Athletics, to listen to Per relay his extensive knowledge and latest research findings.

The most interesting part of day involved his findings showing that tendon loading via targeted resistance training may enhance injury resilience. His findings may warrant a total rethink on current rehab/prehab protocols for athletes prone to tendon injuries.

Tendons are made of collagen fascicles. There are 3 main types of collagen:

Type I: Important for tensile strength
Type II: Main component of cartilage
Type III: Laid down post injury.

It has been previously thought that only muscles can hypertrophy from resistance training and that the tendon and aponeurosis are unaffected.

Interestingly, Aagaard and his colleagues in Denmark have shown in their studies that there was up to 40% increase in the cross sectional area of the tendon after undergoing the resistance-training program compared to the control group. This findings were shown on MRI scan.

MRI scans on athletes involved in sports that predispose an overloading on a leading leg (Fencing, Badminton) confirm such findings.

The training regime involved 12 weeks of heavy resistance knee extension training on a Technogym machine. Subjects trained 3 times per week. They undertook 10 sets of 8 repetitions at 70% of IRM. There was 3 minutes of rest between each set.

The control group consisted of light resistance knee extensions on the other leg under the same conditions.

The benefits of tendon hypertrophy are plentiful. Tendons are essentially elastic and must deform as huge loads are transferred through them.

If the collagen fascicles increase in size then the amount of deformation will be reduced and thus the tendon can absorb more load.

The point at which a tendon will strain is called the ‘Yield Point’. This occurs when the tendon has lost its elasticity and can no longer function within its anatomical limits.

Tendon hypertrophy prevents a tendon reaching the ‘Yield Point’ as early in an untrained tendon. Consequently the muscle will now be able to generate more power within its muscle belly and joint stability will be greatly increased.

Clinical applications in sport should be in the rehabilitation of athletes with previous tendon injuries and in the prehab routines of athletes who are involved in explosive activities that cause massive strain at large tendinous insertions i.e. Semimembranosus and Achilles.

Recap:

•    Heavy resistance training causes hypertrophy of tendons
•    Larger tendons have more strength
•    An increase in tendon stiffness allows more energy to be absorbed
•    Specific training of tendons may help prevent tendon injury


David Cosgrave BSc (Hons) MSc DC
Sports Chiropractor