These results suggest that an early intervention based on NMES superimposed to repeated STSTS exercises is effective for recovering quadriceps strength and symmetry in lower extremity loading by the time of return to sport.

Adding 4-weeks of WBV-OF to a traditional rehabilitation programme 1 month after surgery is effective in improving muscle strength of the knee flexor muscles. This early intervention may be incorporated into current rehabilitation to facilitate early strength recovery of anterior cruciate ligament reconstructed patients.

Purpose Neuromuscular electrical stimulation (NMES) superimposed on voluntary muscle contraction has been recently shown as an innovative training modality within sport and rehabilitation, but its effects on the neuromuscular system are still unclear. The aim of this study was to investigate acute responses in spinal excitability, as measured by the Hoffmann (H) reflex, and in maximal voluntary contraction (MVIC) following NMES superimposed to voluntary isometric contractions (NMES + ISO) compared to passive NMES only and to voluntary isometric contractions only (ISO). Method Fifteen young adults were required to maintain an ankle plantar-flexor torque of 20% MVC for 20 repetitions during each experimental condition (NMES + ISO, NMES and ISO). Surface electromyography was used to record peak-to-peak H-reflex and motor waves following percutaneous stimulation of the posterior tibial nerve in the dominant limb. An isokinetic dynamometer was used to assess maximal voluntary contraction output of the ankle plantar flexor muscles. Results H-reflex amplitude was increased by 4.5% after the NMES + ISO condition (p < 0.05), while passive NMES and ISO conditions showed a decrease by 7.8% (p < 0.05) and no change in reflex responses, respectively. There was no change in amplitude of maximal motor wave and in MVIC torque during each experimental condition. Conclusion The reported facilitation of spinal excitability following NMES + ISO could be due to a combination of greater motor neuronal and corticospinal excitability, thus suggesting that NMES superimposed onto isometric voluntary contractions may provide a more effective neuromuscular stimulus and, hence, training modality compared to NMES alone.

Objectives: To examine whether asymmetrical lower limb loading early after ACL reconstruction (one month) can predict asymmetrical lower limb loading at the time of return to sport (6 months) and whether other early predictors as knee joint range of motion or maximal isometric strength affect this relationship.Design: Ground reaction forces were measured during a sit to stand task (STS) one month after ACL reconstruction and a vertical countermovement jump (CMJ) 6 months after ACL reconstruction in 58 athletes. Other early post-operative measurements were knee joint range of motion (2 weeks, 1 month and 2 months after surgery) and maximal isometric strength of the knee extensor and flexor muscles (2 months after surgery). Linear regression models were developed using side-to-side limb symmetry index (LSI) of CMJ as the dependent variable.Results: LSI of STS 1 month after surgery was a significant independent predictor of LSI of CMJ 6 months after surgery. After accounting for deficits in knee joint range of motion and LSI of maximal isometric strength (ΔR 2 =0.35 p<0.01), LSI of STS predicted LSI of CMJ (ΔR 2 =0.14 p<0.01). Conclusions:Asymmetrical lower extremity loading one month after ACL reconstruction is an early predictor of asymmetrical lower extremity loading 6 months after surgery.

Patients and intervention: Fifteen male athletes following ACL-R using patellar tendon and 11 using hamstrings autograft at the time of return to sport were recruited. Fifteen healthy athletes served as control group. Participants performed 4 different single-leg landing tasks arriving onto a force plate. Main outcome measures: Electromyographic (EMG) activity of knee extensors and flexors, normalized vertical ground reaction force and knee angular displacement were recorded. Results: In all the tasks pre-impact EMG duration was longer in ACL-R (112±28 ms in the knee extensors; 200±34 ms in the knee flexors) compared to healthy participants (74±19 ms in the knee extensors; 153±29 ms in the knee flexors; P<0.05). Initial Contact and Maximum Post-Impact knee angle were lower in ACL-R (9±7 degrees at Initial Contact; 39±12 degrees at maximum flexion) compared to healthy participants (17±9 degrees at Initial Contact; 52±15 degrees at maximum flexion; P<0.05). Normalized vertical GRF was higher in ACL-R compared to healthy participants (3.4±0.5 and 2.7±0.6; P<0.05). Conclusion: At the time of return to sport ACL-R subjects showed altered motor control strategies of single-leg landings. These alterations may lead to uncoordinated movement, hence increasing the risk of re-injury.