Andrea Bailey

Single measurement reliability and reproducibility of volitional and magnetically-evoked indices of neuromuscular performance in adults

This study documents intra-session and inter-day reproducibility (coefficient of variation [V%]) and single measurement reliability (intra-class correlations [R(I)]; standard error of a single measurement [SEM%] [95% confidence limits]) of indices of neuromuscular performance elicited during peripheral nerve magnetic stimulation. Twelve adults (five men and seven women) completed 3 assessment sessions on 3 days, during which multiple assessments of knee flexor volitional and magnetically-evoked indices of electromechanical delay (EMD(V); EMD(E)), rate of force development (RFD(V); RFD(E)), peak force (PF(V); P(T)F(E)), and compound muscle action potential latency (LAT(E)) and amplitude (AMP(E)) were obtained. Results showed that magnetically-evoked indices of neuromuscular performance offered statistically equivalent levels of measurement reproducibility (V%: 4.3-31.2%) and reliability (R(I): 0.98-0.51) compared to volitional indices (V%: 3.7-25.2%; R(I): 0.98-0.64), which support the efficacy of both approaches to assessment and the indices PF(V), EMD(V), EMD(E) and LAT(E) offer the greatest practical utility for assessing neuromuscular performance.

The differential effects of PNF versus passive stretch conditioning on neuromuscular performance

Abstract The effects of flexibility conditioning on neuromuscular and sensorimotor performance were assessed near to full knee extension (25°). Eighteen males who were randomly assigned into two groups underwent eight weeks (three-times per week) of flexibility conditioning (hip region/knee flexor musculature; dominant limb) involving either proprioceptive neuromuscular facilitation (PNF) (n=9) or passive stretching (PASS) (n=9). Both modes of flexibility conditioning are popular within contemporary exercise and clinical settings and have demonstrated efficacy in improving range of motion. The contralateral limb and a prior ‘no exercise’ condition were used as controls. The PNF and PASS modes of conditioning improved passive hip flexibility to a similar extent (mean 19.3% vs. baseline, intervention limb, p<0.01) but did not alter knee flexor strength (overall mean 309.6±81 N) or sensorimotor performance (force and positional errors: 2.3±8.2% and 0.48±7.1%). Voluntary and magnetically evoked electromechanical delays (EMDV and EMDE, respectively) were increased but to a greater extent following PASS compared to PNF (PASS: 10.8% and 16.9% lengthening of EMDV and EMDE, respectively vs. PNF: 3.2% and 6.2%, p<0.01).The attenuated change to electromechanical delay (EMD) performance during PNF conditioning suggests a preserved capability for rapid muscle activation, which is important in the maintenance of dynamic joint stability. That PNF was also equally efficacious in flexibility conditioning would suggest that this mode of flexibility training should be used over passive to help preserve dynamic joint stability capabilities at this extended and vulnerable joint position.

Repeated exercise stress impairs volitional but not magnetically evoked electromechanical delay of the knee flexors

Abstract The effects of serial episodes of fatigue and recovery on volitional and magnetically evoked neuromuscular performance of the knee flexors were assessed in 20 female soccer players during: (i) an intervention comprising 4 × 35 s maximal static exercise, and (ii) a control condition. Volitional peak force was impaired progressively (∼16% vs. baseline: 235.3 ± 54.7 to 198.1 ± 38.5 N) by the fatiguing exercise and recovered to within ∼97 % of baseline values following 6 min of rest. Evoked peak twitch force was diminished subsequent to the fourth episode of exercise (23.3%: 21.4 ± 13.8 vs. 16.4 ± 14.6 N) and remained impaired at this level throughout the recovery. Impairment of volitional electromechanical delay performance following the first episode of exercise (25.5%: 55.3 ± 11.9 vs. 69.5 ± 24.5 ms) contrasted with concurrent improvement (10.0%: 24.5 ± 4.7 vs. 22.1 ± 5.0 ms) in evoked electromechanical delay (P < 0.05), and this increased disparity between evoked and volitional electromechanical delay remained during subsequent periods of intervention and recovery. The fatiguing exercise provoked substantial impairments to volitional strength and volitional electromechanical delay that showed differential patterns of recovery. However, improved evoked electromechanical delay performance might identify a dormant capability for optimal muscle responses during acute stressful exercise and an improved capacity to maintain dynamic joint stabilty during critical episodes of loading.

Antecedent anterior cruciate ligament reconstruction surgery and optimal duration of supervised physiotherapy

A 22-year-old patient undergoing unilateral surgical reconstruction of the anterior cruciate ligament (ACL) of the right knee volunteered for the research project and followed an established contemporary hospital-based rehabilitation programme. The patient was supervised post-surgically by an experienced and clinically specialized physiotherapist. The clinical outcomes of rehabilitation were assessed by selected validated patient-reported and objectively-measured outcomes of functional performance capability on four different occasions (pre-surgery, 6th, 12th and 24th week post-surgery). The patient scored 30, 56, 60 and 85 on IKDC (maximum score, 100); 46, 53, 90 and 91 on Lysholm (maximum score, 100); 141, 73, 128 and 175 on K-SES (maximum score, 220); 17, 12, 6 and 6 on the symptom subsection of KOOS (maximum score, 28); 7, 7, 5 and 5 on the pain subsection (maximum score, 36); 1, 0, 3 and 1 on the daily function subsection (maximum score, 68); 0, 0, 5 and 5 on the sport and recreation function subsection (maximum score, 20); 13, 11, 15 and 13 on the quality of life subsection (maximum score, 16) of KOOS at pre-surgery and at the 6th, 12th and 24th week following ACL reconstruction, respectively. Moreover, the patient scored 1.96 m, 1.92 m and 1.99 m on single-leg hop (injured leg) when assessed at pre-surgery and at the 12th and 24th week post-surgery, respectively, following ACL reconstruction. The total time spent in supervised rehabilitation by the patient (675 minutes) was computed as the aggregate patient-reported time spent in exercise during each hospital-based rehabilitation session (verified by physiotherapist evaluation) across the total number of sessions. The patient managed to return to the sport in which he had participated prior to the injury, immediately after the completion of the contemporary rehabilitation programme, at 24 weeks post-surgery. A total of fifteen physiotherapy sessions supervised by the physiotherapist, were attended by the patient during the 24 week rehabilitation period. The latter number of physiotherapy sessions was substantially less than the average supervised physiotherapy sessions reported in the literature.

Improvement of Outcomes With Nonconcurrent Strength and Cardiovascular-Endurance Rehabilitation Conditioning After ACI Surgery to the Knee

CONTEXT Autologous chondrocyte implantation (ACI) aims to restore hyaline cartilage. Traditionally, ACI rehabilitation is prescribed in a concurrent (CON) format. However, it is well known from studies in asymptomatic populations that CON training produces an interference effect that can attenuate strength gains. Strength is integral to joint function, so adopting a nonconcurrent (N-CON) approach to ACI rehabilitation might improve outcomes. OBJECTIVE To assess changes in function and neuromuscular performance during 48 wk of CON and N-CON physical rehabilitation after ACI to the knee. SETTING Orthopedic Hospital NHS Foundation Trust. DESIGN Randomized control, pilot study. PARTICIPANTS 11 patients (9 male, 2 female; age 32.3 ± 6.6 y; body mass 79.3 ±10.4 kg; time from injury to surgery 7.1 ± 4.9 mo [mean ± SD]) randomly allocated to N-CON:CON (2:1). INTERVENTIONS Standardized CON and N-CON physiotherapy that involved separation of strength and cardiovascular-endurance conditioning. MAIN OUTCOME MEASURES Function in the single-leg-hop test, patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score [KOOS], International Knee Documentation Committee subjective questionnaire [IKDC]), and neuromuscular outcomes of peak force (PF), rate of force development (RFD), electromechanical delay (EMD), and sensorimotor performance (force error [FE]) of the knee extensors and flexors of the injured and noninjured legs, measured presurgery and at 6, 12, 24, and 48 wk postsurgery. RESULTS Factorial ANOVAs with repeated measures of group by leg and by test occasion revealed significantly superior improvements for KOOS, IKDC, PF, EMD, and FE associated with N-CON vs. CON rehabilitation (F(1.5,13.4 GG) = 3.7-4.7, P < .05). These results confirm increased peak effectiveness of N-CON rehabilitation (~4.5-13.3% better than CON over 48 wk of rehabilitation). N-CON and CON showed similar patterns of improvement for single-leg-hop test and RFD. CONCLUSIONS Nonconcurrent strength and cardiovascular-endurance conditioning during 48 wk of rehabilitation after ACI surgery elicited significantly greater improvements to functional and neuromuscular outcomes than did contemporary concurrent rehabilitation.