Background:
Return-to-sports (RTS) rates after anterior cruciate ligament (ACL) reconstruction (ACLR) differ according to the level at which patients return. It is unclear whether the level of RTS is ...affected by psychological readiness to return.
Purpose:
To examine the association between psychological readiness to RTS and subjective RTS level 12 months after ACLR.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
A total of 47 patients who underwent unilateral primary ACLR surgery were enrolled. Assessments at 6 and 12 months postoperatively consisted of knee strength testing (isokinetic quadriceps and hamstring strength), the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC-SKF), and the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale to measure psychological readiness to RTS. Patients were assigned to 1 of 3 subgroups based on their subjective assessment of RTS level at 12 months postoperatively: RTS at or above preinjury level (RTS≥Pre; n = 19), RTS below preinjury level (RTS<Pre; n = 24), or no RTS (n = 4). Two-way mixed-model analysis of variance was used to examine the effects of RTS subgroup, postoperative time point, and group × time interaction with patient characteristics, knee strength, and IKDC-SKF and ACL-RSI scores. Multivariate logistic regression analysis was performed to determine which factors were associated with RTS subgroupings.
Results:
Significant differences were found among the RTS≥Pre, RTS<Pre, and no-RTS groups in age, ACL-RSI score at 6 and 12 months, quadriceps strength at 6 and 12 months, and IKDC-SKF score at 6 and 12 months (P < .001 for all). Multivariate logistic regression analysis revealed that RTS at or above preinjury level was associated with higher ACL-RSI score at 12 months postoperatively (odds ratio OR, 1.11; 95% CI, 1.05-1.20; P = .003) and younger age (OR, 0.80; 95% CI, 0.61-0.92; P = .012).
Conclusion:
The ACL-RSI score was significantly different among the study groups, and the ACL-RSI score at 12 months postoperatively and younger age were associated with RTS at or above preinjury level.
PURPOSE This study aimed to present isokinetic quadriceps and hamstring muscle strength values in K league 1 (K1) professional soccer players and compare these results to those of published studies. ...METHODS A total of 31 K1 soccer players (age 24.5±4.2) without a history of lower limb injury were included in this study. Isokinetic knee strength tests were implemented at a velocity of 60°·s-1 and 180°·s-1 for both dominant (D) and non-dominant (ND) legs using a dynamometer. Strength variables included peak torque (PT), body mass normalized PT (NPT), bilateral strength difference (BD), and hamstring to quadriceps strength (H/Q) ratio. RESULTS At 60°·s-1 velocity, the NPTs of the quadriceps were 3.39N·m·kg-1 and 3.33N·m·kg-1 for D and ND legs, respectively, and those of the hamstrings were 2.00N·m·kg-1 and 1.89N·m·kg-1 for D and ND legs, respectively. At 180°·s-1 velocity, the NPTs of the quadriceps were 2.31N·m·kg-1, 2.27N·m·kg-1 for D and ND legs, respectively, and those of the hamstrings were 1.42N·m·kg-1, 1.39N·m·kg-1 for D and ND legs, respectively. At all velocities, the BDs of quadriceps and hamstring muscles ranged from 6.6–7.8%, and H/Qs ranged from 57–62%. Compared to previous studies that did not consider the history of injury, this study showed lower levels of BD (less than 10%) and higher levels of NPT. CONCLUSIONS The presented isokinetic quadriceps and hamstring muscle strength values can be used as reference values for the isokinetic knee strength of K1 professional soccer players.
Older adults have the highest incidence of domestic ladder falls, but little investigation has been given to this important injury issue. There is therefore a need to understand the influence of ...individual factors like physical and cognitive ability and psychological status on safe and effective ladder use in this population. This study investigated associations between vision, lower and upper limb sensation, upper limb control, strength, balance, cognitive function and psychological status with task completion time and number of ladder moves taken in a simulated roof gutter clearing task on a straight ladder in 97 older adults. Several measures from upper limb control, strength, balance, processing speed, executive function and psychological domains were significantly associated with the two ladder task performance measures. Upper limb bimanual coordination, knee extension strength, coordinated leaning balance, and self-reported risk-taking were identified as independent and significant predictors of task completion time in a multiple regression model, predicting 56% of the variability in ladder task completion time. Upper limb bimanual coordination and proprioception, simple reaction time and coordinated leaning balance were independent and significant predictors of the number of ladder moves in a separate multiple regression model, predicting 38% of the variability in ladder moves taken. These findings help identify individuals at greater ladder fall risk and can guide ladder fall interventions, such as strength and balance training, ladder design and targeted safety instructions.
•Older adults have a high incidence of domestic ladder falls.•Ladder falls often occur while clearing a roof gutter.•Physical, cognitive and psychological factors influence gutter clearing performance.•Dexterity, strength, balance & risk-taking independently predicted task performance.•These findings can guide ladder fall interventions for older adults.
OBJECTIVES: To assess the relationship between rate of change in muscle strength and all‐cause mortality.
DESIGN: Prospective observational study of the causes and course of physical disability.
...SETTING: Twelve contiguous ZIP code areas in Baltimore, Maryland.
PARTICIPANTS: Three hundred seven community‐dwelling women aged 70 to 79 at study baseline.
MEASUREMENTS: The outcome was all‐cause mortality (1994–2009); predictors included up to seven repeated measurements of handgrip, knee extension, and hip flexion strength, with a median follow‐up time of 10 years. Demographic factors, body mass index, smoking status, number of chronic diseases, depressive symptoms, physical activity, interleukin‐6, and albumin were assessed at baseline and included as confounders. The associations between declining muscle strength and mortality were assessed using a joint longitudinal and survival model.
RESULTS: Grip and hip strength declined an average of 1.10 and 1.31 kg/year between age 70 and 75 and 0.50 and 0.39 kg/year thereafter, respectively; knee strength declined at a constant rate of 0.57 kg/year. Faster rates of decline in grip and hip strength, but not knee strength, independently predicted mortality after accounting for baseline levels and potential confounders (hazard ratio (HR)=1.33, 95% confidence interval (95% CI)=1.06–1.67, HR=1.14, 95% CI=0.91–1.41, and 2.62, 95% CI=1.43–4.78 for every 0.5 standard deviation increase in rate of decline in grip, knee, and hip strength, respectively).
CONCLUSION: Monitoring the rate of decline in grip and hip flexion strength in addition to absolute levels may greatly improve the identification of women most at risk of dying.
Rehabilitation after anterior cruciate ligament (ACL) reconstruction focuses on restoring knee deficiencies and function. However, the extent of the clinician's direct supervision that is required to ...recover knee function is unknown.
To investigate differences in isokinetic knee strength improvement, endurance, and proprioception between home-based (HBR) and supervised rehabilitation (SR).
Thirty participants were randomly allocated to each group after reconstruction. Isokinetic knee strength and proprioception were measured using the Biodex multi-joint and stability systems, respectively, before and after intervention.
The SR group showed a significant improvement from baseline, but not the HBR group (SR group, from 1.94 ± 1.44 to 1.02 ± 0.92, p< 0.05; HBR group, from 1.69 ± 0.88 to 1.61 ± 0.90, p> 0.05). There was a significant effect of exercise type on proprioception scores after controlling for pretest values (p< 0.05). No significant difference in isokinetic knee strength was observed between the groups.
HBR recovered knee strength as effectively as the SR, but SR was more effective than HBR for the recovery of proprioception and functional knee movement. This result indicates that guidance from health professionals play an important role in enhancing proprioception for patients following ACL reconstruction.
Obese (OB) youth demonstrate altered knee mechanics and worse lower-extremity performance compared with healthy weight (HW) youth. Our objectives were to compare sagittal plane knee landing mechanics ...between OB and HW youth and to examine the associations of knee and hip extension peak torque with landing mechanics in OB youth. Twenty-four OB and 24 age- and sex-matched HW youth participated. Peak torque was measured and normalized to leg lean mass. Peak knee flexion angle and peak internal knee extension moment were measured during a single-leg hop landing. Paired t tests, Pearson correlation coefficients, and Bonferroni corrections were used. OB youth demonstrated worse performance and lower knee extension (OB: 12.76 1.38, HW: 14.03 2.08, P = .03) and hip extension (OB: 8.59 3.13, HW: 11.10 2.89, P = .005) peak torque. Furthermore, OB youth demonstrated lower peak knee flexion angles (OB: 48.89 45.41 to 52.37, HW: 56.07 52.59 to 59.55, P = .02) and knee extension moments (OB: -1.73 -1.89 to -1.57, HW: -2.21 -2.37 to -2.05, P = .0001) during landing compared with HW youth. Peak torque measures were not correlated with peak knee flexion angle nor internal knee extension moment during landing in either group (P > .01). OB youth demonstrated altered landing mechanics compared with HW youth. However, no associations among peak torque measurements and knee landing mechanics were present.
The quantification of muscle weakness is useful to evaluate the health status and performance of patients and athletes. In this paper, we proposed a novel methodology to investigate and to quantify ...the effects induced by inaccuracy sources occurring when using a hand-held dynamometer (HHD) for knee strength measurements. The validation methodology is based on the comparison between the output of a one-component commercial HHD and the outputs of a six-component load cell, comparable in dimension and mass. An optoelectronic system was used to measure HHD positioning angles and displacements. The setup allowed to investigate the effects induced by: the operator's ability to place and to hold still the HHD and ignoring the transversal components of the force exchanged. The main finding was that the use of a single component HHD induced an overall inaccuracy of 5% in the strength measurements if the angular misplacements are kept within the values found in this paper (≤15°) and with a knee range of motion ≤22°. Extension trials were the most critical due to the higher force exerted, i.e., 249.4 ± 27.3 versus 146.4 ± 23.9 N of knee flexion. The most relevant source of inaccuracy was identified in the angular displacement on the horizontal plane.
While many studies investigated inter-limb asymmetries (ILAs) in different athletes, little is known about ILAs in the population of gymnasts. The first aim of our study was to compare differences ...between gymnasts and their non-gymnast peers in isometric knee maximal and rapid strength parameters (peak torque - PT and rate of torque development - RTD) and countermovement jump (CMJ) parameters (height, maximal force), as well as in ILAs in all outcome measures. The second aim of the study was to assess the relationship between ILA of maximal force and the ILAs of the isometric knee strength parameters. 15 gymnasts (aged 11.19 ± 1.89 years) and 15 non-gymnasts (aged 10.92 ± 1.96 years) performed unilateral isometric maximal voluntary contractions of the knee flexors and extensors on a dynamometer and CMJ on a force plate. ILAs were calculated and compared between groups across all outcome measures. We found that gymnasts reached statistically significant better results than non-gymnasts in most isometric knee strength parameters and CMJ height, but not on RTD of left knee flexion and maximal force in the CMJ. Meanwhile, we did not find significant differences between groups in ILAs. Linear regression showed no correlations between the ILAs measures separately for the groups. Even though we did not find any differences between the groups in the ILAs, we should be aware of it to prevent injury in young girls.
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