FlyWheel Training (FWT) study: eccentric overload training on a flywheel ergometer versus standard excentric training for the treatment of patellar tendinopathy in athletes.

Jumper's knee or patellar tendinopathy is an injury of the patellar tendon and
is a common injury in sports, among elite and non-elite athletes. Despite of
the high prevalence in athletes, there is still no effective treatment and
return-to-sport is often many weeks or even months. Earlier research showed an
overall prevalence among elite athlets of 14%, up to 45% and 32% in volleyball
and basketball athletes (Liam et al, 2011). Among non-elite athletes there is
an overall prevalence of 8,5%, up to 14% for volleyball playres (Zwerver,
2011). There is no effective treatment for patellar tendinopathy, no treatment
brings the athlete back to previous sports level in an acceptable period of
time (Zwerver 2011, Cook et al, 2001, Gaida et al, 2011).

At this moment, treatment consist of prolonged rehabilitation to restore the
balance between capacity and load (Zwerver et al, 2008). Eccentric exercises
are the main component of most treatment protocols.

Eccentric training could have a positive effect and improve clinical status and
function in patients diagnosed with chronic tendinopathy. Eccentric muscle
contraction is a contraction with lengthening of the muscle-tendon-complex.
Squat exercises and exercises on a decline board, both forms of eccentric
training, showed positive results in pain reduction and return to sport.
Eccentric training by squat-exercises using a flywheel provides a reinforcement
of the eccentric action, which is called an eccentric overload.

The flywheel is accelerated by the upward component of a squat (concentric
action of the m. quadriceps). During the downward (eccentric) component of a
squat the accelerated flywheel ensures a downward weight which is decelerated
by the patient. This downward weight is proportional to the forces delivered by
the patient during the upward component of a squat, even if this is greatly
reduced due to tiredness, at the end of the exercise. In other words, the
acceleration of the flywheel and subsequently the eccentric overload are
determined by the concentric power delivered by the patient.

Eccentric training by using a flywheel showed in earlier research a higher EMG
activity, with a muscle activation close to maximal in both the concentric and
eccentric exercises. Beside this a hypertrophy of the quadriceps was measured
after three weeks of overload eccentric training on a flywhel ergometer.
Another study on the effect of eccentric training by using a leg-press flywheel
ergometer on patients with patellar tendinopathy, showed a reduction of
subjective pain after six weeks of training.

Our hypothesis is that overload eccentric training on a flyweel ergometer,
guided by a physiotherapist, is more effective in reducing pain and a faster
return to sport versus standard eccentric training for athletes with patellar
tendinopathy.

The objective of this study is to evaluate if overload eccentric training on a
flywheel ergometer, guided by a physiotherapist, is an appropriate training for
athletes with patellar tendinopathy to reduce pain and a faster return to
sport. The pain and exercise capacity will be measured by the NL-VISA-P.

Our recent (pilot)study showed improvement of pain and function in just 6 weeks
(Timmermans et al, 2012, report internship VUmc)

Our research question:
Is overload eccentric training on a flywheel ergometer more effective in
reducing pain and improving exercise capacity measured by the NL-VISA-P versus
standard eccentric training in athletes with patellar tendinopathy?

The study is a multicenter randomised controlled trial looking at the effect of
treatment of patellatendinopathy with overload excentric training using a
flywheel compared to standard eccentric training.

The diagnosis is confirmed by a sports physician with experience in patella
tendinopathy.

After inclusion there is determination of the VAS score at 3 functional tests
and VISA-P.

The Flywheel group will be assigned to 6 weeks (2 sessions per week) of
overload excentric training using a flywheel ergometer, supervised by a
physical therapist.

The Standard group is assigned to 6 weeks (2 sessions per week) standard
eccentric training, supervised by a physical therapist. .

Supervised overload eccentric training of the patellar tendon using a flywheel
ergometer.

Burden:

One extra physical examination is performed

Filling out questionnaires (general questionnaire and NL-VISA-P) at 6 measuring
moments

Three functional tests are requested by an independent physical therapist

The actual training consists of 6 weeks of training, 2 times a week 30 minutes
(for both groups)