Mr Benji Dutaillis

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.

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.

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 ± 3yrs; height, 164 ± 5 cm; and weight, 58 ± 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.

Anterior cruciate ligament (ACL) injury and reconstructive surgery is known to cause long-term negative impacts on quadriceps muscle size. With the known link between reduced muscle size and the health and functioning of the knee joint, it is important rehabilitation programs aim to restore quadriceps mass as safely and quickly as possible. However, a comprehensive review of interventions investigating the impact of training interventions on quadriceps muscle size in ACL-reconstructed individuals has yet to be undertaken. Therefore, this article systematically reviews the evidence investigating training interventions that aim to improve quadriceps size in ACL-reconstructed individuals. A literature search was performed in MEDLINE, SPORTDiscus, CINAHL, and Web of Science. Observational and experimental studies investigating training interventions impact on quadriceps muscle size in ACL-reconstructed individuals were included. Risk-of-bias assessment (Downs and Black) was completed on included studies, data was extracted, and a best evidence synthesis was undertaken. 718 articles were returned in the initial search; following screening, six articles were included in this review. Results from the best evidence synthesis suggest there is moderate evidence for eccentrically biased training to increase quadriceps size. Both traditional resistance training and blood flow restriction training showed conflicting results for improving quadriceps size. However, the results for traditional resistance training and blood flow restriction training may have been limited by differing imaging methods across included studies. This review highlights the positive changes in quadriceps size seen following traditional, eccentrically biased and blood flow restriction exercise interventions in ACL-reconstructed limbs, despite the limited number of studies. Further work is needed to identify and optimize the best practice for hypertrophic training in these individuals.