ABSTRACT
AIM: Examine age-related differences in muscle size and strength of the knee extensors in individuals with cerebral palsy (CP) and individuals with typical development (TD). METHODS: 54 individuals with CP (14.5 ± 4.5 years, GMFCS I-V) and 33 individuals with TD (16.2 ± 5.5 years) were included. Relationships between rectus femoris (RF) and vastus lateralis (VL) muscle volume and isokinetic knee extensor strength with age were examined with linear regression and ANCOVA to test age-related differences between groups. RESULTS: Linear regression for muscle volume with age was statistically significant in TD (VL: r2 = 0.48, RF: r2 = 0.56, p < .05) and those with CP (VL: r = 0.36, RF: r2 = 0.27, p < .05) with no differences in regression slopes between groups (p > .05). Age-related strength differences were observed in TD (r2 = 0.66, p < .001) and those with CP (r2 = 0.096, p = .024), but the slopes were significantly different between CP and TD (p < .001). CONCLUSION: Age-related linear differences in muscle volume and strength were observed in both groups. The linear slope of the age-related differences in knee extensor muscle strength and strength-to-body mass ratio were significantly lower in individuals with CP compared to individuals with TD, suggesting that strength is insufficient to keep up with gains in body mass during growth.
ABSTRACT
BACKGROUND: Lower extremity muscle power influences walking ability in individuals with Cerebral Palsy (CP). AIM: Determine the reliability, validity, and minimal detectable change (MDC) of a novel power leg press (PLP) test to measure muscle power in individuals with CP. METHODS: Individuals with spastic CP (n = 26 (10 adults, 16 children); mean (SD) age = 19.3 (7.8) years(all); 27.9 (4.89) years (adults); 13.85(2.68) years (children)) performed 2 sessions of the PLP test, 2-10 days apart. A linear position transducer and custom computer code were used to calculate mean and peak power in watts (W). Intraclass correlation coefficients (ICC), standard error of measurement, MDC, and percent change of MDC (MDC%) were calculated for 4 power measures (average and maximum of mean and peak powers) for all participants (AP) and separately for adults (A) and children (C). Validity was evaluated against isokinetic knee extensor power. RESULTS: Test-retest reliability was excellent for all measures of power (ICC = 0.94-0.99). Ranges for MDC/MDC% by the group for power measures were between 33.7-80.7W/15.5-29.4% (AP), 41.1-65.3W/10.7-22.3% (A), and 27.6-79.8W/19-34.3% (C). Correlations were good to excellent between PLP and isokinetic power at all speeds (r = 0.75-0.88, p < .001). CONCLUSIONS: The PLP test demonstrates excellent validity, reliability, and precision for measuring muscle power in those with CP.
Subject(s)
Cerebral Palsy , Leg , Adult , Child , Humans , Young Adult , Reproducibility of Results , Lower Extremity , WalkingABSTRACT
PURPOSE: The purpose of this study was to standardize 1-repetition maximum (1-RM) testing procedures and evaluate the safety and feasibility of these procedures in youth with cerebral palsy (CP). METHODS: Youth with CP completed 1-RM testing on a leg press. RESULTS: Mean absolute, adjusted, and normalized 1-RM loads were 262.4 ± 161.3 lb, 127.0 ± 80.2 lb, and 1.28 ± 0.51, respectively, and 67% were able to successfully lift the same or heavier load after a single failure. Cessation of testing after 1 failed attempt resulted in a 19.0% underestimation of the 1-RM. CONCLUSIONS: 1-RM testing in youth with CP is safe and feasible. Multiple attempts at a failed load should be provided to prevent underestimation in strength. The 1-RM test provides a more accurate strength assessment, which will improve the dosing for resistance training in youth with CP.
Subject(s)
Cerebral Palsy , Resistance Training , Adolescent , Child , Feasibility Studies , Humans , Muscle Strength , Muscle, Skeletal , Resistance Training/methods , Weight LiftingABSTRACT
BACKGROUND: Generalized joint laxity is more prevalent in women than men and may lead to poorer post-operative outcomes in select orthopedic populations. There are no studies examining peri-operative function in patients with generalized joint laxity (GJL) and femoroacetabular impingement (FAI). PURPOSE: The purpose of this study was to determine the difference in perceived function and quality of life as measured by the Hip Outcome Score ADL subscale (HOS-ADL), International Hip Outcomes Tool (iHOT-33) and the Short Form 12-Item Health Survey (SF-12) in women with and without GJL prior to and six months after undergoing hip arthroscopy for FAI. STUDY DESIGN: Cohort Study. METHODS: Peri-operative data were collected from women with FAI from November 2011-September 2014. Lax subjects were women with laxity scores ≥4/9 on the Beighton and Horan Joint Mobility Index; Nonlax subjects were women with laxity scores <4/9. Functional outcomes were evaluated using the HOS-ADL, iHOT-33, PCS-12, and the MCS-12 pre-operatively and at 6 months post-operatively. Change scores (post-score - pre-score) were calculated for each outcome measure and compared between groups, along with pre-operative and post-operative means, using Mann-Whitney U tests. RESULTS: 166 women met the inclusion criteria: Nonlax (n = 131), Lax (n = 35). There were no statistically significant differences between groups in pre-operative functional outcomes (all p > .05). Additionally, there were no statistically significant differences between groups in post-operative means or change scores, respectively, for HOS-ADL (p = .696, .358), iHOT-33 (p = .550, .705), PCS-12 (p = .713, .191), and MCS-12 (p = .751, .082). Laxity score was not associated with any post-operative functional outcome score or change score (all p > .05). CONCLUSION: Women with and without generalized joint laxity do not appear to report differences in hip function in the 6-month peri-operative period before and after hip arthroscopy for FAI. LEVEL OF EVIDENCE: 3.
