Thirty-seven females, aged initially between 10 and 13.5 years, completed a mixed longitudinal study over 3.3 years to investigate the effect of training volume and growth upon gymnastic performance. Gymnasts undergoing high volume training (mean = 30 hrs/week: Group 1) and moderate volume training (mean = 15 hrs/week: Group 2) were tested at 4-month intervals on growth measures including height, mass, skinfolds, and segment lengths, as well as the strength of lower limb, upper limb, and trunk musculature. Functional gymnastic development was observed through the assessment of generic, whole body rotation tasks, a vertical jump, and a v-sit action. The high training volume gymnasts were significantly smaller but markedly stronger than those gymnasts in Group 2 despite the size disadvantage. Consequently, Group 1 gymnasts were able to produce higher velocities for front and backward rotations and a faster v-sit action. These training group differences remained significant after initial size differences were taken into account via an analysis of covariance.
Joanne E. Richards, Timothy R. Ackland and Bruce C. Elliott
Timothy R. Ackland, Peter W. Henson and Donald A. Bailey
The effect of the uniform density assumption upon estimation of body segment inertial parameters was examined by employing directly measured, CT-derived, and cadaver-derived density values. Sectional and average density values for the right leg segments of a patient 29 years of age and a cadaver (65 years) were obtained with a GE 9800 computed tomography scanner using dual energy radiographic factors of 80 kV, 200 mAs, and 140 kV, 200 mAs. Careful sectioning of the cadaver leg following these scans permitted mass and density measurements to be directly performed. The results for both legs showed marked variation in cross-section density values throughout their lengths, which highlighted the limitations of the assumption of uniform segment density. The effect of employing this assumption was tested using a series of inertial parameter estimation strategies by means of mathematical modeling. Adoption of the uniform density assumption when estimating inertial parameters of the human leg segment was shown to produce only minor errors. However, greater errors were shown to be caused by inaccurate estimates of segment volume.
Jay R. Ebert, Anne Smith, Peter K. Edwards and Timothy R. Ackland
Matrix-induced autologous chondrocyte implantation (MACI) is an established technique for the repair of knee chondral defects. Despite the reported clinical improvement in knee pain and symptoms, little is known on the recovery of knee strength and its return to an appropriate level compared with the unaffected limb.
To investigate the progression of isokinetic knee strength and limb symmetry after MACI.
Private functional rehabilitation facility.
58 patients treated with MACI for full-thickness cartilage defects to the femoral condyles.
MACI and a standardized rehabilitation protocol.
Main Outcome Measures:
Preoperatively and at 1, 2, and 5 y postsurgery, patients underwent a 3-repetition-maximum straight-leg raise test, as well as assessment of isokinetic knee-flexor and -extensor torque and hamstring:quadriceps (H:Q) ratios. Correlation analysis investigated the association between strength and pain, demographics, defect, and surgery characteristics. Linear-regression analysis estimated differences in strength measures between the operated and nonoperated limbs, as well as Limb Symmetry Indexes (LSI) over time.
Peak knee-extension torque improved significantly over time for both limbs but was significantly lower on the operated limb preoperatively and at 1, 2, and 5 y. Mean LSIs of 77.0%, 83.0%, and 86.5% were observed at 1, 2, and 5 y, respectively, while 53.4–72.4% of patients demonstrated an LSI ≤ 90% across the postoperative timeline. Peak knee-flexion torque was significantly lower on the operated limb preoperatively and at 1 year. H:Q ratios were significantly higher on the operated limb at all time points.
While peak knee-flexion and hip-flexor strength were within normal limits, the majority of patients in this study still demonstrated an LSI for peak knee-extensor strength ≤ 90%, even at 5 y. It is unknown how this prolonged knee-extensor deficit may affect long-term graft outcome and risk of reinjury after return to activity.
Peter K. Edwards, Jay R. Ebert, Gregory C. Janes, David Wood, Michael Fallon and Timothy Ackland
Matrix-induced autologous chondrocyte implantation (MACI) has become an established technique for the repair of chondral defects in the knee. MACI has traditionally required an open arthrotomy, but now lends itself to an arthroscopic technique, which may decrease the associated comorbidity of arthrotomy, potentially allowing for faster rehabilitation.
To compare postoperative outcomes between arthroscopic and open arthrotomy techniques of MACI and present a case for faster recovery and accelerated rehabilitation after surgery.
Retrospective cohort study.
Private functional rehabilitation facility.
78 patients (41 arthroscopic, 37 open) treated with MACI for full-thickness cartilage defects to the femoral condyles.
According to surgeon preference, patients recruited over the same time period underwent MACI performed arthroscopically or via a conventional open arthrotomy. Both surgical groups were subjected to an identical rehabilitation protocol.
Main Outcome Measures:
Patient-reported (Knee Injury and Osteoarthritis Outcome Score, Short Form Health Survey, and visual analogue scale) and functional (6-min-walk test, 3-repetition straight-leg-raise test [3R-SLR]) outcomes were compared presurgery and at 3, 6, and 12 mo postsurgery. Active knee range of motion (ROM) was additionally assessed 4 and 8 wk postsurgery. MRI evaluation was assessed using magnetic-resonance observation of cartilage-repair tissue (MOCART) scores at 3 and 12 mo. The length of hospital stay was evaluated, while postsurgery complications were documented.
Significant improvements (P < .05) for both groups were observed over the 12-mo period for patient-reported and functional outcomes; however, the arthroscopic cohort performed significantly better (P < .05) in active knee-flexion and -extension ROM and the 3R-SLR. No differences were observed in MOCART scores between the 2 groups at 12 mo. Patients who received arthroscopic implantation required a significantly reduced (P < .001) hospital stay and experienced fewer postoperative complications.
Arthroscopic MACI in combination with “best practice” rehabilitation has shown encouraging early results, with good clinical outcomes to 12 mo, reduced length of patient hospitalization, and reduced risk of postsurgery complications. This may have important implications for postoperative rehabilitation and a faster return to full function.