Differences in muscle strength after ACL reconstruction do not influence cardiorespiratory responses to isometabolic exercise
Carregando...
Data
2014-04
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
Objectives: To investigate whether the muscle strength decrease that follows anterior cruciate ligament
(ACL) reconstruction would lead to different cardiorespiratory adjustments during dynamic exercise. Method:
Eighteen active male subjects were submitted to isokinetic evaluation of knee flexor and extensor muscles four months
after ACL surgery. Thigh circumference was also measured and an incremental unilateral cardiopulmonary exercise
test was performed separately for both involved and uninvolved lower limbs in order to compare heart rate, oxygen
consumption, minute ventilation, and ventilatory pattern (breath rate, tidal volume, inspiratory time, expiratory time,
tidal volume/inspiratory time) at three different workloads (moderate, anaerobic threshold, and maximal). Results:
There was a significant difference between isokinetic extensor peak torque measured in the involved (116.5±29.1 Nm)
and uninvolved (220.8±40.4 Nm) limbs, p=0.000. Isokinetic flexor peak torque was also lower in the involved limb
than in the uninvolved limb (107.8±15.4 and 132.5±26.3 Nm, p=0.004, respectively). Lower values were also found in
involved thigh circumference as compared with uninvolved limb (46.9±4.3 and 48.5±3.9 cm, p=0.005, respectively).
No differences were found between the lower limbs in any of the variables of the incremental cardiopulmonary tests at
all exercise intensities. Conclusions: Our findings indicate that, four months after ACL surgery, there is a significant
deficit in isokinetic strength in the involved limb, but these differences in muscle strength requirement do not produce
differences in the cardiorespiratory adjustments to exercise. Based on the hypotheses from the literature which explain the
differences in the physiological responses to exercise for different muscle masses, we can deduce that, after 4 months of
a rehabilitation program after an ACL reconstruction, individuals probably do not present differences in muscle oxidative
and peripheral perfusion capacities that could elicit higher levels of peripheral cardiorepiratory stimulus during exercise.
Descrição
Palavras-chave
Rehabilitation, Ventilatory response, Anterior cruciate ligament, Oxygen uptake, Isokinetic testing, Physical therapy
Citação
ANDRADE, Marília S. et al. Differences in muscle strength after ACL reconstruction do not influence cardiorespiratory responses to isometabolic exercise. Brazilian Journal of Physical Therapy, São Carlos, v. 18, p. 144-151, Mar./Apr. 2014.