Concurrent validity and test-retest reliability of VALD ForceDecks' strength, balance, and movement assessment tests.

OBJECTIVES: To evaluate the concurrent validity and test-retest reliability of common movement, strength, and balance tests using portable uniaxial dual force plates. DESIGN: Repeated measures cross-sectional study. METHODS: Sixteen healthy individuals participated in two testing sessions, where they performed 12 different movement, strength, and balance tests. Vertical ground reaction force and centre of pressure data were collected using the VALD ForceDecks simultaneously with ground-embedded laboratory force plates. Concurrent validity was assessed using root mean square error for raw time-series data and Bland-Altman plots for discrete metrics. Test-retest reliability was assessed using intraclass correlation coefficients and minimal detectable changes. RESULTS: ForceDecks recorded vertical ground reaction forces and center of pressure with high accuracy compared to laboratory force plates. The mean bias between systems was negligible (<2 N or 0.1 mm), with small limits of agreement (<5 N or 1 mm). Overall, 530/674 (79%) showed good or excellent validity (<10% difference) and 611/773 (79%) had good or excellent reliability (intraclass correlation coefficient >0.75). ForceDecks reliability was similar to laboratory force plates (<0.07 intraclass correlation coefficient median difference for all metrics). CONCLUSIONS: Portable uniaxial force plates record highly accurate vertical ground reaction forces and center of pressure during a range of movement, strength, and balance tests. The VALD ForcDecks are a valid and reliable alternative to laboratory force plates when strict standardized testing and data analysis procedures are followed. Users should be aware of the validity and reliability characteristics of the tests and metrics they choose.

Vertical Jump Testing after Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis.

INTRODUCTION: Recently, there has been a call for vertical jump testing via force-plate analysis to be included in the assessment of individuals after anterior cruciate ligament reconstruction (ACLR) and as part of return-to-play criteria. However, a synthesis of current literature is needed to help guide clinicians on what tests to perform, which force-plate metrics to assess, and how these may change over the time course of rehabilitation. METHODS: Four online databases were searched from inception to July 2022. The Downs and Black checklist was used to assess study quality. Multilevel meta-analyses and meta-regressions were undertaken in conjunction with a best evidence synthesis. RESULTS: Forty-two articles were included, capturing 2375 participants with a history of ACLR. Reconstructed limbs displayed 1) lower peak eccentric forces, concentric forces, landing forces, and lower eccentric and concentric impulses (standardized means difference [SMD] = -1.84 to -0.46) than uninjured contralateral limbs during bilateral countermovement jumps (CMJ) and drop vertical jumps (DVJ); 2) lower jump heights and reactive strength indices (RSI), and longer contact times than uninjured contralateral limbs during unilateral CMJ and DVJ (SMD = -0.86 to 0.26); and 3) lower jump heights, RSI, and longer contact times during bilateral and unilateral CMJ, and unilateral DVJ, than uninjured controls (SMD = -1.19 to 1.08). Meta-regression revealed that time postsurgery was a significant moderator ( P < 0.05) for 1) bilateral CMJ height, peak concentric force, and peak landing force; 2) between-limb differences in unilateral CMJ height; and 3) differences in unilateral DVJ height, RSI, and contact time between reconstructed limbs and healthy controls with no history of injury. CONCLUSIONS: Individuals with a history of ACLR display chronic deficits in vertical jumping performance during a range of bilateral and unilateral tasks, which may have implications for return-to-play criteria and the design of interventions targeted at restoring long-term deficits in explosive lower limb strength after ACLR.

Trunk, pelvis and lower limb coordination between anticipated and unanticipated sidestep cutting in females.

BACKGROUND: Emerging research has suggested a plausible relationship may exist between lower limb coordination and musculoskeletal injury. A small number of studies have investigated the link between coordination and anterior cruciate ligament (ACL) injury during sidestep cutting. While prior work has shown unanticipated sidestep cutting to exhibit a more 'at risk' kinematic profile compared to anticipated tasks, a detailed understanding of the coordination between multiple joints and how they differ during unanticipated actions is lacking, particularly in females. RESEARCH QUESTION: The purpose of this study was to observe the difference in trunk, pelvis and lower limb coordination and coordination variability during a dynamic, sidestep cutting task under anticipated and unanticipated conditions in a healthy female cohort. METHODS: Three-dimensional motion analysis data were recorded during anticipated and unanticipated sidestep cutting for nineteen healthy female participants (age, 24 ±â€¯3yrs; height, 164 ±â€¯5 cm; and weight, 58 ±â€¯6 kg). Vector coding methodology was used to calculate coordination and coordination variability values and statistical parametric and non-parametric mapping was used to comprehensively determine differences between anticipated and unanticipated conditions. RESULTS: Differences were observed between anticipated and unanticipated conditions in the hip flexion - knee abduction angle (89 % of stance), hip rotation - knee abduction angle (55 % of stance), knee flexion - knee abduction angle (81-83 %, 86 % and 88-89 %) and knee flexion - ankle flexion angle (14-18 %) coupling angles. Differences in coupling angle variability were also observed with only one cluster of significance seen in hip abduction - knee abduction variability (27-30 % of stance). SIGNIFICANCE: Healthy females exhibit significant differences in lower limb coupling angles and coupling angle variability between anticipated and unanticipated sidestep cutting. Interventions aimed at reducing ACL injury risk may need to consider that anticipated and unanticipated sidestep cutting tasks present unique demands, and therefore should both be trained specifically.

Lower Limb Muscle Size after Anterior Cruciate Ligament Injury: A Systematic Review and Meta-Analysis.

BACKGROUND: Anterior cruciate ligament (ACL) injury is known to have a number of deleterious effects on lower limb muscle function. Alterations in muscle size are one such effect that have implications towards reductions in strength and functioning of the lower limbs. However, a comprehensive analysis of alterations in muscle size has yet to be undertaken. OBJECTIVE: To systematically review the evidence investigating lower limb muscle size in ACL injured limbs. DESIGN: Systematic review DATA SOURCES: Database searches of Medline, SPORTDiscus, Embase, Cinahl and Web of Science as well as citation tracking and manual reference list searching. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Individuals with ACL deficient or reconstructed limbs with an assessment of lower limb muscle size and control limb data (contralateral or uninjured control group) METHODS: Risk of bias assessment was completed on included studies. Data were extracted and where possible meta-analyses performed. Best evidence synthesis was also undertaken. RESULTS: 49 articles were included in this review, with 37 articles included in the meta-analyses. 66 separate meta-analyses were performed using various measures of lower limb muscle size. Across all measures, ACL deficient limbs showed lesser quadriceps femoris muscle size (d range = - 0.35 to - 0.40), whereas ACL reconstructed limbs showed lesser muscle size in the quadriceps femoris (d range = - 0.41 to - 0.69), vastus medialis (d = - 0.25), vastus lateralis (d = - 0.31), hamstrings (d = - 0.28), semitendinosus (d range = - 1.02 to - 1.14) and gracilis (d range = - 0.78 to - 0.99) when compared to uninjured limbs. CONCLUSION: This review highlights the effect ACL injury has on lower limb muscle size. Regardless of whether an individual chooses a conservative or surgical approach, the quadriceps of the injured limb appear to have lesser muscle size compared to an uninjured limb. When undertaking reconstructive surgery with a semitendinosus/gracilis tendon graft, the harvested muscle shows lesser muscle size compared to the uninjured limb.