A performance comparison of neuromuscular electrical stimulation protocols for isolated quadriceps contraction versus co-contraction of quadriceps and hamstrings.

A Neuromuscular Electrical Stimulation (NMES) protocol that incorporates co-contraction of the quadriceps and hamstrings may provide greater functional benefits for knee rehabilitation. It is unclear if the addition of a co-contraction will affect the desired torque outputs of one or two of the involved muscle groups. Due to the proposed functional benefits of co-contraction, it may be beneficial to test the addition of a co-contraction electrical muscle stimulation. In this study we recruited 14 participants with whom we compared two NMES protocols; isolated quadriceps contraction (k-NMES) versus co-contraction of quadriceps and hamstrings (co-NMES). We examined peak knee extension evoked torque, current intensities required to produce given torque outputs, and self-reported discomfort levels at given torques. At maximum tolerable intensity peak torque output was similar in k-NMES versus co-NMES. To achieve specific submaximal levels of torque output as percentages of maximum voluntary contraction (MVC), a higher current intensity was required for co-NMES yet with no greater level of discomfort. Results suggest that clinicians who wish to achieve a co-contraction of quadriceps and hamstrings as part of a rehabilitation programme can use co-NMES without having to sacrifice the strength of contraction achieved in the quadriceps. This could lead to better functional outcomes, though more work is required to confirm this.

Clinical and biomechanical outcomes of rehabilitation targeting intersegmental control in athletic groin pain: prospective cohort of 205 patients.

BACKGROUND: Clinical assessments and rehabilitation in athletic groin pain (AGP) have focused on specific anatomical structures and uniplanar impairments rather than whole body movement. OBJECTIVE: To examine the effectiveness of rehabilitation that targeted intersegmental control in patients with AGP and to investigate post rehabilitation changes in cutting biomechanics. METHODS: Two hundred and five patients with AGP were rehabilitated focusing on clinical assessment of intersegmental control, linear running and change of direction mechanics in this prospective case series. Hip and Groin Outcome Score (HAGOS) was the primary outcome measure. Secondary measures included pain-free return to play rates and times, pain provocation on squeeze tests and three-dimensional (3D) biomechanical analysis during a 110° cutting manoeuvre. RESULTS: Following rehabilitation, patients demonstrated clinically relevant improvements in HAGOS scores (effect size (ES): 0.6-1.7). 73% of patients returned to play pain-free at a mean of 9.9 weeks (±3.5). Squeeze test values also improved (ES: 0.49-0.68). Repeat 3D analysis of the cutting movement demonstrated reductions in ipsilateral trunk side flexion (ES: 0.79) and increased pelvic rotation in the direction of travel (ES: 0.76). Changes to variables associated with improved cutting performance: greater centre of mass translation in the direction of travel relative to centre of pressure (ES: 0.4), reduced knee flexion angle (ES: 0.3) and increased ankle plantar flexor moment (ES: 0.48) were also noted. CONCLUSIONS: Rehabilitation focused on intersegmental control was associated with improved HAGOS scores, high rates of pain-free return to sporting participation and biomechanical changes associated with improved cutting performance across a range of anatomical diagnoses seen in AGP.