Hand-held dynamometry (HHD) has never previously been used to examine isometric muscle power. Rate of force development (RFD) is often used for muscle power assessment, however no consensus currently ...exists on the most appropriate method of calculation. The aim of this study was to examine the reliability of different algorithms for RFD calculation and to examine the intra-rater, inter-rater, and inter-device reliability of HHD as well as the concurrent validity of HHD for the assessment of isometric lower limb muscle strength and power.
30 healthy young adults (age: 23±5 yrs, male: 15) were assessed on two sessions. Isometric muscle strength and power were measured using peak force and RFD respectively using two HHDs (Lafayette Model-01165 and Hoggan microFET2) and a criterion-reference KinCom dynamometer. Statistical analysis of reliability and validity comprised intraclass correlation coefficients (ICC), Pearson correlations, concordance correlations, standard error of measurement, and minimal detectable change.
Comparison of RFD methods revealed that a peak 200 ms moving window algorithm provided optimal reliability results. Intra-rater, inter-rater, and inter-device reliability analysis of peak force and RFD revealed mostly good to excellent reliability (coefficients ≥ 0.70) for all muscle groups. Concurrent validity analysis showed moderate to excellent relationships between HHD and fixed dynamometry for the hip and knee (ICCs ≥ 0.70) for both peak force and RFD, with mostly poor to good results shown for the ankle muscles (ICCs = 0.31-0.79).
Hand-held dynamometry has good to excellent reliability and validity for most measures of isometric lower limb strength and power in a healthy population, particularly for proximal muscle groups. To aid implementation we have created freely available software to extract these variables from data stored on the Lafayette device. Future research should examine the reliability and validity of these variables in clinical populations.
Abstract The revised Xbox One Kinect, also known as the Microsoft Kinect V2 for Windows, includes enhanced hardware which may improve its utility as a gait assessment tool. This study examined the ...concurrent validity and inter-day reliability of spatiotemporal and kinematic gait parameters estimated using the Kinect V2 automated body tracking system and a criterion reference three-dimensional motion analysis (3DMA) marker-based camera system. Thirty healthy adults performed two testing sessions consisting of comfortable and fast paced walking trials. Spatiotemporal outcome measures related to gait speed, speed variability, step length, width and time, foot swing velocity and medial–lateral and vertical pelvis displacement were examined. Kinematic outcome measures including ankle flexion, knee flexion and adduction and hip flexion were examined. To assess the agreement between Kinect and 3DMA systems, Bland–Altman plots, relative agreement (Pearson's correlation) and overall agreement (concordance correlation coefficients) were determined. Reliability was assessed using intraclass correlation coefficients, Cronbach's alpha and standard error of measurement. The spatiotemporal measurements had consistently excellent ( r ≥0.75) concurrent validity, with the exception of modest validity for medial–lateral pelvis sway ( r =0.45–0.46) and fast paced gait speed variability ( r =0.73). In contrast kinematic validity was consistently poor to modest, with all associations between the systems weak ( r <0.50). In those measures with acceptable validity, the inter-day reliability was similar between systems. In conclusion, while the Kinect V2 body tracking may not accurately obtain lower body kinematic data, it shows great potential as a tool for measuring spatiotemporal aspects of gait.
Evaluate change in functional performance from 1- to 5-years after anterior cruciate ligament reconstruction (ACLR).
59 participants (38 men) aged 29 ± 16 years completed three hops and one-leg rise ...1- and 5-years following ACLR. Linear mixed-effects models evaluated differences in change between the ACLR and contralateral limbs. Participants were classified with stable, improving or worsening function relative to previously published minimal detectable change thresholds. Healthy controls completed the three hops (n = 41) and one-leg rise (n = 31) as reference data.
The contralateral limb had a significantly greater decrease in functional performance between 1- and 5-years for the three hops, compared to the ACLR limb. Worsening was more common in the contralateral limb than the ACLR limb; resulting in significant improvements in the LSI for the single hop (mean 87% at 1-year to 95% at 5-years), side hop (77%to 86%) and one-leg rise (76% to85%). Performance of both ACLR and contralateral limbs and the LSI remained below the healthy controls.
Functional performance changes differ between limbs between 1- and 5-years post-ACLR. The LSI should not be used in isolation to evaluate functional performance changes after ACLR, as it may overestimate functional improvement, due to worsening contralateral limb function.
•The contralateral limb had a significantly greater decrease in function for the three hop tests compared to the ACLR limb.•The LSI improved significantly for the single hop, side hop and one-leg rise between 1- and 5-years post-ACLR.•The LSI overestimate improvement in functional ability following ACLR, due to worsening contralateral limb function.•The LSI on all four tests at 1-year post-ACLR was significantly lower than healthy controls.
Background:
Patellofemoral joint (PFJ) osteoarthritis may occur after anterior cruciate ligament reconstruction (ACLR). The mechanisms underpinning the development of PFJ osteoarthritis are not known ...but may relate to altered PFJ loading. Few studies have assessed PFJ loads during high-impact tasks, such as running, beyond the acute rehabilitation phase (ie, >12 months) after ACLR.
Purpose/Hypothesis:
The purpose was to compare between-limb joint angles, joint moments, and PFJ contact force during running in individuals at 12 to 24 months after unilateral ACLR. We hypothesized that peak knee flexion angle, knee extension moment, and PFJ contact force during stance would be lower in the ACLR limb compared with the uninjured limb.
Study Design:
Controlled laboratory study.
Methods:
A total of 55 participants (mean ± SD age, 28 ± 7 years), 12 to 24 months after ACLR, ran at a self-selected speed (2.9 ± 0.3 m/s). Measured kinematics and ground-reaction forces were input into musculoskeletal models to calculate joint moments and muscle forces. These values were subsequently input into a PFJ model to calculate contact force peak and impulse. Outcome measures were compared between the ACLR and uninjured limbs.
Results:
In the ACLR limb, compared with the uninjured limb, the PFJ contact force displayed a lower peak (ACLR, 6.1 ± 1.3 body weight BW; uninjured, 6.7 ± 1.4 BW; P < .001) and impulse (ACLR, 0.72 ± 0.17 BW*seconds BWs; uninjured, 0.81 ± 0.17 BWs; P < .001). At the time of the peak PFJ contact force, the knee extension moment was lower in the ACLR limb (ACLR, 14.0 ± 2.4 %BW*height %BW*HT; uninjured, 15.5 ± 2.5 %BW*HT; P < .001). The opposite was true for the ankle plantarflexion moment (ACLR, 12.1 ± 2.6 %BW*HT; uninjured, 11.5 ± 2.7 %BW*HT; P = .019) and the hip extension moment (ACLR, 2.3 ± 2.5 %BW*HT; uninjured, 1.6 ± 2.3 %BW*HT; P = .013). The foot-ground center of pressure was located more anteriorly with respect to the ankle joint center (ACLR, 5.8 ± 0.9 %height %HT; uninjured, 5.4 ± 1.0 %HT; P = .001). No differences were found for the sagittal plane hip, knee, and ankle angles.
Conclusion:
The ACLR limb experienced lower peak PFJ loads during running, explained by a small anterior shift in the foot-ground center of pressure during stance that offloaded the torque demand away from the ACLR knee.
Clinical Relevance:
Lower net PFJ loading during running in the ACLR limb more than 12 months after ACLR suggests that underloading might play a role in the onset of PFJ osteoarthritis after ACLR.
The physical demands of professional tennis combined with high training/match loads can contribute to musculoskeletal injury. The objectives of this study were to (1) describe the type, location and ...severity of injuries sustained during a 12-month tennis season in a cohort of professional female tennis players on the Women's Tennis Association (WTA) tour and (2) prospectively investigate associations between training/match loads and injury.
52 WTA players competing at the Australian Open (2015) consented to participate. Injuries reported to WTA medical staff were classified using tennis-specific guidelines. Individual match exposure data were collected for all matches played at international level in 2015 and expressed per 1000 hours of WTA competition matchplay (MP) and 1000 match exposures (MEs). Variables associated with the number of injuries in the season and loss of time from competition were identified with regression analysis.
The injury incidence rate (IR) was 56.6 (95% CI: 49.5 to 64.6) per 1000 hours of MP or 62.7 (95% CI: 54.8 to 71.6) per 1000 MEs, although the IR of injuries resulting in loss of time from competition was lower (12.8 per 1000 hours of MP, 92 injuries/100 players). Lower limb (51%) and muscle/tendon (50%) injuries were the most common site and type of injury. Common specific injury site subcategories were the thigh, shoulder/clavicle, ankle and knee in order of frequency. Various measures of match load were significantly associated with injury.
This study prospectively analysed injury profiles, including severity across an entire season of professional tennis, and investigated the relationship between training/match loads and injury. These data may help medical professionals develop injury risk identification and prevention programmes.
Rationale, aims and objectives Previous systematic reviews have concluded that exercise programmes are effective in the management of clinical depression. The aim of this review was to analyse the ...parameters of exercise programmes reported in the primary research, in order to provide clinicians with evidence‐based recommendations for exercise prescription for clinical depression.
Methods A systematic review of randomized controlled trials was undertaken. Only trials that reported exercise to be effective in treating depression were included and our review was limited to adults. Appropriate databases and reference lists were searched using established keywords. Data relating to the type, intensity, frequency, duration, mode of exercise and mode of application of exercise was extracted and collated.
Results A total of 14 randomized controlled trials were included in this review and from these trials 20 intervention arms were analysed. The majority of trials used an aerobic exercise intervention and were supervised. The most common exercise parameters were 60–80% of maximum heart rate for 30 minutes three times per week for an overall duration of 8 weeks. There is an equal volume of evidence supporting group as opposed to individually completed exercise programmes and no trends were identified which would support one mode of exercise over another.
Conclusions Currently the primary research on this topic supports the use of aerobic exercise which is supervised in some capacity. The current evidence base supports a prescription of three 30‐minute sessions per week of aerobic exercise at 60–80% of maximum heart rate for at least 8 weeks.
Altered biomechanics are frequently observed following anterior cruciate ligament reconstruction (ACLR). Yet, little is known about knee‐joint loading, particularly in the patellofemoral‐joint, ...despite patellofemoral‐joint osteoarthritis commonly occurring post‐ACLR. This study compared knee‐joint reaction forces and impulses during the landing phase of a single‐leg forward hop in the reconstructed knee of people 12‐24 months post‐ACLR and uninjured controls. Experimental marker data and ground forces for 66 participants with ACLR (28 ± 6 years, 78 ± 15 kg) and 33 uninjured controls (26 ± 5 years, 70 ± 12 kg) were input into scaled‐generic musculoskeletal models to calculate joint angles, joint moments, muscle forces, and the knee‐joint reaction forces and impulses. The ACLR group exhibited a lower peak knee flexion angle (mean difference: −6°; 95% confidence interval: −10°, −2°), internal knee extension moment (−3.63 −5.29, −1.97 percentage of body weight × participant height (body weight BW × HT), external knee adduction moment (‐1.36 −2.16, −0.56% BW × HT) and quadriceps force (−2.02 −2.95, −1.09 BW). The ACLR group also exhibited a lower peak patellofemoral‐joint compressive force (−2.24 −3.31, −1.18 BW), net tibiofemoral‐joint compressive force (−0.74 −1.20, 0.28 BW), and medial compartment force (−0.76 −1.08, −0.44 BW). Finally, only the impulse of the patellofemoral‐joint compressive force was lower in the ACLR group (−0.13 −0.23, −0.03 body weight‐seconds). Lower compressive forces are evident in the patellofemoral‐ and tibiofemoral‐joints of ACLR knees compared to uninjured controls during a single‐leg forward hop‐landing task. Our findings may have implications for understanding the contributing factors for incidence and progression of knee osteoarthritis after ACLR surgery.
Patellofemoral joint (PFJ) osteoarthritis is common following anterior cruciate ligament reconstruction (ACLR) and may be linked with altered joint loading. However, little is known about the ...cross‐sectional and longitudinal relationship between PFJ loading and osteoarthritis post‐ACLR. This study tested if altered PFJ loading is associated with prevalent and worsening early PFJ osteoarthritis post‐ACLR. Forty‐six participants (mean ± 1 SD age 26 ± 5 years) approximately 1‐year post‐ACLR underwent magnetic resonance imaging (MRI) and biomechanical assessment of their reconstructed knee. Trunk and lower‐limb kinematics plus ground reaction forces were recorded during the landing phase of a standardized forward hop. These data were input into a musculoskeletal model to calculate the PFJ contact force. Follow‐up MRI was completed on 32 participants at 5‐years post‐ACLR. Generalized linear models (Poisson regression) assessed the relationship between PFJ loading and prevalent early PFJ osteoarthritis (i.e., presence of a PFJ cartilage lesion at 1‐year post‐ACLR) and worsening PFJ osteoarthritis (i.e., incident/progressive PFJ cartilage lesion between 1‐ and 5‐years post‐ACLR). A lower peak PFJ contact force was associated with prevalent early PFJ osteoarthritis at 1‐year post‐ACLR (n = 14 30.4%; prevalence ratio: 1.37; 95% confidence interval CI: 1.02–1.85) and a higher risk of worsening PFJ osteoarthritis between 1‐ and 5‐years post‐ACLR (n = 9 28.1%; risk ratio: 1.55, 95% CI: 1.13–2.11). Young adults post‐ACLR who exhibited lower PFJ loading during hopping were more likely to have early PFJ osteoarthritis at 1‐year and worsening PFJ osteoarthritis between 1‐ and 5‐years. Clinical interventions aimed at mitigating osteoarthritis progression may be beneficial for those with signs of lower PFJ loading post‐ACLR.
The Microsoft Xbox One Kinect™ (Kinect V2) contains a depth camera that can be used to manually identify anatomical landmark positions in three-dimensions independent of the standard skeletal ...tracking, and therefore has potential for low-cost, time-efficient three-dimensional movement analysis (3DMA). This study examined inter-session reliability and concurrent validity of the Kinect V2 for the assessment of coronal and sagittal plane kinematics for the trunk, hip and knee during single leg squats (SLS) and drop vertical jumps (DVJ). Thirty young, healthy participants (age = 23 ± 5yrs, male/female = 15/15) performed a SLS and DVJ protocol that was recorded concurrently by the Kinect V2 and 3DMA during two sessions, one week apart. The Kinect V2 demonstrated good to excellent reliability for all SLS and DVJ variables (ICC ≥ 0.73). Concurrent validity ranged from poor to excellent (ICC = 0.02 to 0.98) during the SLS task, although trunk, hip and knee flexion and two-dimensional measures of knee abduction and frontal plane projection angle all demonstrated good to excellent validity (ICC ≥ 0.80). Concurrent validity for the DVJ task was typically worse, with only two variables exceeding ICC = 0.75 (trunk and hip flexion). These findings indicate that the Kinect V2 may have potential for large-scale screening for ACL injury risk, however future prospective research is required.
•First study to evaluate dynamic time-to-boundary during stair use post ACLR.•Altered medial-lateral postural control during stair descent post ACLR.•Clinical relevance of altered medial-lateral ...postural control needs investigation.
Dynamic postural control during everyday tasks is poorly understood in people following anterior cruciate ligament reconstruction (ACLR). Understanding dynamic postural control can provide insight into potentially modifiable impairments in people following ACLR who are at increased risk for second ACL injury and/or knee osteoarthritis.
Determine whether measures indicative of dynamic postural control differ between individuals with and without ACLR during stair ascent and descent. Methods: Seventeen individuals with ACLR (>1 yr post-surgery) and 16 age and sex-matched healthy controls participated. Centre of pressure (COP) measures included: i) COP excursion, ii) COP velocity, and iii) dynamic time-toboundary (TTB). Mixed linear models were used to compare COP measures for the ACLR leg, non-ACLR leg, and healthy controls during stair ascent and stair descent.
There were no statistically significant differences observed during stair ascent (all p > 0.05). Several statistical differences were found during stair descent for individual with ACLR, but not between those with ACLR and healthy controls. The ACLR leg had higher medial-lateral COP excursion (mean difference 1.06 cm, 95 %CI 0.08–2.06 cm, p = 0.036; effect size = 0.38) compared to the non-ACLR leg during stair descent. In addition, the ACLR leg had a lower medial-lateral TTB (mean difference −13 ms 95 %CI −38 to 2 ms, p = 0.005; effect size = 0.49) and medial-lateral TTB normalized to stance time (mean difference −5.8 % 95 %CI −10.3 to 1.3 %, p = 0.012; effect size = 0.80) compared to the non-ACLR leg during stair descent. No statistical differences were observed for anterior-posterior measures during stair descent (all p > 0.05). Significance: Taken together, findings indicate that there are small to large differences in medial-lateral postural control in the ACLR leg compared to the non-ACLR leg during stair descent. Further work is required to understand clinical implication of these novel observations.
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