Objectives: The use of microsensor technologies to conduct research and implement interventions in sports and exercise medicine has increased recently. The objective of this paper was to determine the validity and reliability of the ViPerform as a measure of load compared to vertical ground reaction force (GRF) as measured by force plates. Design: Absolute reliability assessment, with concurrent validity. Methods: 10 professional triathletes ran 10 trials over force plates with the ViPerform mounted on the mid portion of the medial tibia. Calculated vertical ground reaction force data from the ViPerform was matched to the same stride on the force plate. Bland–Altman (BA) plot of comparative measure of agreement was used to assess the relationship between the calculated load from the accelerometer and the force plates. Reliability was calculated by intra-class correlation coefficients (ICC) with 95% confidence intervals. Results: BA plot indicates minimal agreement between the measures derived from the force plate and ViPerform, with variation at an individual participant plot level. Reliability was excellent (ICC = 0.877; 95% CI = 0.825–0.917) in calculating the same vertical GRF in a repeated trial. Standard error of measure (SEM) equalled 99.83 units (95% CI = 82.10–119.09), which, in turn, gave a minimum detectable change (MDC) value of 276.72 units (95% CI = 227.32–330.07). Conclusions: The ViPerform does not calculate absolute values of vertical GRF similar to those measured by a force plate. It does provide a valid and reliable calculation of an athlete’s lower limb load at constant velocity.
Objectives Forearm injuries are common and debilitating to elite rowers. Chronic exertional compartment syndrome, intersection syndrome and proximal radial bone stress injuries have been documented in this population. This paper explores the imaging findings related to these conditions in asymptomatic elite rowers. Design Observational study. Methods 19 asymptomatic senior elite and under-23 rowers currently competing at National level or above underwent ultrasound (US), Magnetic Resonance Imaging (MRI) and muscle functional MRI evaluation of their forearms. A comprehensive evaluation sheet identifying characteristics of bone stress, intersection syndrome and chronic exertional compartment syndrome was utilised based on a literature search and review by senior clinicians working with this population. Results Peritendinous fluid of Extensor Carpi Radialis Longus (n=10, 53%) or Extensor Carpi Radialis Brevis (n=6, 32%) was a common finding on US. MRI had a higher rate of identification than US. Extensor Digitorum (Coeff=−1.76, 95%CI −3.04 to −0.49), Flexor Carpi Radialis (Coeff=−2.86, 95%CI −5.35 to −0.38) and Flexor Carpi Ulnaris (Coeff=−3.31, 95%CI −5.30 to −1.32), Pronator Teres (Coeff=−3.94, 95%CI −6.89 to −0.99), and Supinator (Coeff=−168, 95%CI −3.28 to −0.02) showed statistically significant changes immediately post-exercise. Mild proximal radial marrow hyperintensity was present (n=15, 78.9%) with three participants (15.8%) also having mild periosteal oedema of the radius. Conclusions Imaging findings commonly seen in symptomatic populations are observed in elite, asymptomatic rowers. Care should be taken when diagnosing bone stress injuries, intersection syndrome and compartment syndrome on imaging findings alone. Data presented can be utilised as a normative dataset for future case studies.