The assessment of loading during walking and running has historically been limited to data collection in laboratory settings or with devices that require a computer connection. This study aims to determine if the loadsol®—a single sensor wireless insole—is a valid and reliable method of assessing force. Thirty (17 male and 13 female) recreationally active individuals were recruited for a two visit study where they walked (1.3 m/s) and ran (3.0 and 3.5 m/s) at a 0%, 10% incline, and 10% decline, with the visits approximately one week apart. Ground reaction force data was collected on an instrumented treadmill (1440 Hz) and with the loadsol® (100 Hz). Ten individuals completed the day 1 protocol with a newer 200 Hz loadsol®. Intraclass correlation coefficients (ICC3,k) were used to assess validity and reliability and Bland–Altman plots were generated to better understand loadsol® validity. Across conditions, the peak force ICCs ranged from 0.78 to 0.97, which increased to 0.84–0.99 with the 200 Hz insoles. Similarly, the loading rate ICCs improved from 0.61 to 0.97 to 0.80–0.96 and impulse improved from 0.61 to 0.97 to 0.90–0.97. The 200 Hz insoles may be needed for loading rate and impulse in running. For both walking and running, the loadsol® has excellent between-day reliability (>0.76).

Clinically feasible methods for quantifying landing kinetics could help identify patients at risk for secondary anterior cruciate ligament injuries. The purpose of this study was to evaluate the validity and between-day repeatability of the loadsol insole during a single-hop and bilateral stop-jump. Thirty healthy recreational athletes completed seven single-hops and seven stop-jumps while simultaneous loadsol (100 Hz) and force plate (1920 Hz) measurements were recorded. Peak impact force, loading rate, and impulse were computed for the dominant limb, and limb symmetry was calculated between limbs for each measure. All outcomes were compared between the loadsol and force plate using intraclass correlation coefficients (ICC) and Bland–Altman plots. Fifteen participants completed a second day of testing to assess between-day repeatability of the loadsol. Finally, an additional 14 participants completed the first day of testing only to assess the validity of the newest generation loadsol, which sampled at 200 Hz. At 100 Hz, validity ICC results were moderate to excellent (0.686–0.982), and repeatability ICC results were moderate to excellent (0.616–0.928). The 200 Hz loadsol demonstrated improved validity ICC (0.765–0.987). Bland–Altman plots revealed that the loadsol underestimated load measures. However, this bias was not observed for symmetry outcomes. The loadsol device is a valid and repeatable tool for evaluating kinetics during landing.

There is limited literature that follows a population of Anterior Cruciate Ligament Reconstruction (ACLR) patients through recovery. Our aim was to examine differences in movement and loading patterns across time and between limbs over four visits during 12 months post-ACLR. We hypothesized that kinematic and kinetic data during a stop-jump would have time- and limb-dependent differences through 12 months post-surgery. Twenty-three ACLR athletes performed five vertical stop-jumps at 4, 5, 6, and 12 months post-op with motion capture and force plate data collection. The peak knee flexion (PKF) was different between the 4 and 12, 5 and 6, and the 5 and 12 month visits with earlier months exhibiting higher PKF. The peak vertical ground reaction force (vGRF) was lower at 4 than at 5 and 6 months. The peak posterior ground reaction force (pGRF) was lower at 4 months than all other visits. Frontal knee and sagittal hip range of motion (ROM) were different between 12 months and each previous visit. Asymmetries were present in peak vGRF, peak knee extension moment and impulse up to 12 months. The loading rate and peak pGRF demonstrated between limb differences up to 6 months; limb stiffness demonstrated differences up to 5 months post-ACLR. PKF was only asymmetric at the 4 month visit. While some variables improved in the 12 months post-ACLR, limb asymmetries in peak knee extension moment, peak vGRF and impulse persisted up to 12 months. Additionally, frontal plane knee and sagittal hip ROM had not normalized at 12 months. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1887-1893, 2018.

Purpose Hop tests are widely used to quantify recovery from anterior cruciate ligament reconstruction (ACLR) surgery. However, there is evidence that simply measuring hop distance may not be indicative of the quality of movement or representative of potential limitations in hopping mechanics, particularly during landing. The first purpose of the present study was to compare hop distance and loading symmetry between ACLR athletes and healthy uninjured recreational athletes. The second was to determine the association between hop distance and loading symmetry. Methods Twenty-five ACLR patients and 30 healthy controls completed the single hop, triple hop, and crossover hop test on each limb while the loadsol®, a single-sensor force insole, collected impact forces (100 Hz). A limb symmetry index (LSI) was calculated for hop distance, peak impact force, loading rate, and impulse from the final landing of each trial. LSI values were compared between groups using Mann–Whitney U tests, and distance and loading LSI values were compared using Spearman rank correlations. Results ACLR patients had reduced symmetry in hop distance and loading relative to healthy controls for every hop test and outcome measure (P < 0.05), except peak impact force on the single hop. Hop distance symmetry was significantly related to each loading symmetry measure on the crossover hop test (P < 0.01) and to peak impact force and impulse symmetry on the single hop test (P < 0.05) in each group. Conclusion This study demonstrates that ACLR patients both hop further and generate larger forces when hopping on their nonsurgical limb relative to their surgical limb. In addition, hop distance and loading symmetry provide clinicians and researchers with different information and therefore should be considered together when making return to sport decisions.

No abstract