The use of eccentrically biased resistance exercise to mitigate muscle impairments following anterior cruciate ligament reconstruction: a short review

Abstract

Background: Novel interventions that can safely and effectively overload muscle early following anterior cruciate ligament reconstruction are needed to minimize atrophy and weakness that often becomes longstanding.

Evidence acquisition: Eccentrically induced forces can be safely applied during the early stages of rehabilitation following surgery and serve as a potent stimulus for increasing muscle size and strength.

Results: Compared to a standard rehabilitation program, adding an early 12-week eccentric resistance-training program 3 weeks after anterior cruciate ligament reconstruction induces improvement in quadriceps and gluteus maximus volume at 15 weeks and at 1 year after surgery. Likewise, those who performed an eccentrically biased rehabilitation program also achieved greater improvements in quadriceps strength and hopping ability measured at 15 weeks and at 1 year after surgery.

Clinical relevance: There is potential to safely and feasibly perform eccentric contractions as part of a formal rehabilitation program following anterior cruciate ligament reconstruction.

Keywords: anterior cruciate ligament reconstruction; eccentric; outcomes; rehabilitation.

Figure 1.

Two eccentric ergometers. As the pedals move toward the participant (to the right in these figures) resistance is applied to the pedals from approximately 20° to 60° of knee flexion in a closed kinetic-chain fashion. Because the magnitude of force produced by the motor exceeds that produced by the participant, the knee and hip extensors act eccentrically, creating negative work. (Reprinted from Marcus RL, Smith S, Morrell G, et al. Comparison of combined aerobic and high-force eccentric resistance exercise with aerobic exercise only for people with type 2 diabetes mellitus. Physical Therapy. 2008;88(11):1345-1354, with permission of the American Physical Therapy Association. This material is copyrighted, and any further reproduction or distribution is prohibited.)

Figure 2.

Comparison of quadriceps volume between the eccentric and standard rehabilitation groups of both the involved and uninvolved thighs at 3 weeks (pretraining), at 15 weeks (post-training), and at 1 year (post-training) after ACL reconstruction. Values represent the means (error bars = 1 SD).

Figure 3.

Mid-thigh, axial, T1-weighted magnetic resonance images of a subject assigned to the eccentric-exercise group. Quadriceps volume of the involved thigh was 30% less than the uninvolved thigh at 3 weeks post–ACL-R (pretraining). Quadriceps volume improved 28% at 15 weeks post–ACL-R (post-training) and 32% overall at 1 year post–ACL-R.

Figure 4.

Comparison of quadriceps strength (isokinetic peak torque) between the eccentric and standard rehabilitation groups of both the involved and uninvolved thighs before ACL reconstruction, and at 15 weeks (post-training) and at 1 year (post-training) after surgery. Values represent the means (error bars = 1 SD

Figure 5.

Comparison of one leg hopping distance between the eccentric and standard rehabilitation groups of both the involved and uninvolved lower extremities before anterior cruciate ligament reconstruction, and at 15 weeks (post-training) and at 1 year (post-training) after surgery. Values represent the means (error bars = 1 SD).