Differences in muscle strength after ACL reconstruction do not influence cardiorespiratory responses to isometabolic exercise

Abstract

ObjectivesTo investigate whether the muscle strength decrease that follows anterior cruciate ligament (ACL) reconstruction would lead to different cardiorespiratory adjustments during dynamic exercise. MethodEighteen 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). ResultsThere 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. ConclusionsOur 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.

Anterior cruciate ligament deficiency reduces walking economy in “copers” and “non-copers”

“…The loss of strength in our ACL‐deficient patients appears as another appealing explanation for their reduced walking economy; studies in athletes have shown that strength training is accompanied by increased strength of lower limbs and improved running economy [1, 20, 40]. However, a recent study in ACL‐deficient patients failed to find differences in oxygen consumption when supine exercise was performed with affected or unaffected limb, despite the lower strength of the ACL‐deficient leg [4]. The above findings suggest that the lower gait economy in ACL‐deficient patients is rather explained by the higher effort required to overcome gait instability and not by the strength of lower limbs per se.…”

Fisioterapi Pada Kasus Post Anterior Cruciate Ligament Reconstruction (Aclr): A Case Report

“…Selain itu, pasien post ACLR akan mengalami penurunan kekuatan otot secara signifikan, terutama pada otot quadriceps. Hal ini dimungkinkan oleh karena peran protektif tubuh dalam upaya menstabilkan lutut yang kehilangann fungsi ACL sebagai penahan translasi tibialis ke anterior (Andrade et al, 2014). Meskipun mekanisme saraf yang memandu respons ini tidak diketahui, aktivitas saraf yang berubah setelah cedera ACL telah direkam dengan baik pada tingkat spinal dan kortikal, dan secara negatif mempengaruhi kemampuan untuk menghasilkan kontraksi otot (Lepley et al, 2020).…”

Association of Congenital Heart Disease Among theNeonate-Children with Their Maternal Diabetes

“…ACL reconstruction (ACLR) is useful for joint stability restoration and highly indicated in young athletes who want to regain their sport level (prior level before injury). But surgery can lead to muscle disuse and disorders particularly during the 3 first months [2], with a high risk of iterative injuries [3]. Lower limb function is altered at different levels (muscle strength, trophicity fatigability and neural drive,) and these alterations remain until functional recovery [4,5].…”