muscle function after rehabilitation with cryotherapy in patients with anterior
cruciate ligament reconstruction.

Hart JM, Kuenze CM, Diduch
DR and Ingersoll CD. J Athl Training.
[Epub Ahead of Print].

Home Message: Among knees with a history of anterior cruciate ligament (ACL)
reconstruction and chronic quadriceps dysfunction, the application of
cryotherapy prior to performing exercises may help mitigate arthrogenic muscle
inhibition and improve muscle function.

Following ACL reconstruction, patients
often suffer from persistent quadriceps weakness potentially caused by arthrogenic
muscle inhibition. If clinicians could reduce arthrogenic muscle inhibition
then patients may be able to increase quadriceps strength.  Therefore, Hart and colleagues compared
quadriceps muscle function in patients treated with cryotherapy, exercise, or
both. The authors included 30 participants who had undergone ACL reconstruction
at least 6 months prior to the study, and were cleared for physical activity by
their physician. At baseline, the authors measured the patients’ quadriceps
activation and quadriceps
Hoffmann reflex. To assess quadriceps activation,
patients sat and performed 2 to 3 maximum voluntary isometric contractions of
the quadriceps. As their torque reached plateau, the researchers applied an
electrical stimulus to increase torque above the maximum voluntary isometric
contraction value. The central activation ratio was defined as the torque
generated by a maximum voluntary isometric contraction divided by the electrically
stimulated activation. The authors measured Quadriceps Hoffmann reflex by
applying a short electrical stimuli to the patient’s femoral nerves (electrode
placed in the inguinal fold) in a supine position. After baseline testing, researchers
randomized the participants into 1 of 3 treatment groups for a 2-week
intervention. Participants in the cryotherapy group applied 2 ice bags to the
anterior and posterior sides of the knee for 20 minutes everyday. Participants in
the exercise group, performed a 1-hour long, progressive exercise program
daily. Participants randomized to the combination group performed cryotherapy
for 20 minutes followed by the same exercise program as performed by the
exercise group. All participants attended four supervised treatment sessions
during the 2-week period. Patients’ quadriceps activation and Hoffmann reflex
were measured following the 2-week intervention. Overall there were no
significant differences between any of the treatment groups for any variables. However,
there was trends indicating that participants who received both cryotherapy and
exercise increased knee extension torque while participants in the cryotherapy
group or exercise group did not.

Overall, the current study provides
preliminary support for the use of cryotherapy prior to exercise in patients
who have undergone ACL reconstruction and who have chronic quadriceps muscle
dysfunction. The results of this study should be particularly interesting to
clinicians as it shows how cryotherapy can be beneficial in mitigating
arthrogenic muscle inhibition as well as pain. By using cryotherapy prior to
the exercises, clinicians could reduce the muscle inhibition during the
exercises and maximize the benefits of an exercise program. More research will
be needed to determine if cryotherapy prior to exercises is also effective
among patients with different injuries as well as varying levels of pre-injury
activity, amounts of quadriceps inhibition, times since injury, ages, and delays
between surgery and intervention. Until this can be done however, clinicians
should use cryotherapy to treat pain and possibly muscle inhibition throughout
the rehabilitation process.

Questions for Discussion: Have you used cryotherapy prior
to exercise to help improve quadriceps activation? When do you use cryotherapy?

Written by: Kyle Harris
Reviewed by: Jeffrey Driban 

Related Posts:

Hart, J., Kuenze, C., Diduch, D., & Ingersoll, C. (2014). Quadriceps Muscle Function After Rehabilitation With Cryotherapy in Patients With Anterior Cruciate Ligament Reconstruction Journal of Athletic Training DOI: 10.4085/1062-6050-49.3.39