Reliability of Force Plate Metrics During Standard Jump, Balance, and Plank Assessments in Military Personnel

Abstract

Introduction Prevention of musculoskeletal injury is vital to the readiness, performance, and health of military personnel with the use of specialized systems (e.g., force plates) to assess risk and/or physical performance of interest. This study aimed to identify the reliability of one specialized system during standard assessments in military personnel. Methods Sixty-two male and ten female Australian Army soldiers performed a two-leg countermovement jump (CMJ), one-leg CMJ, one-leg balance, and one-arm plank assessments using a Sparta Science force plate system across three testing sessions. Sparta Science (e.g., total Sparta, balance and plank scores, jump height, and injury risk) and biomechanical (e.g., average eccentric rate of contraction, average concentric force, and sway velocity) variables were recorded for all sessions. Mean ± SD, intraclass correlation coefficients (ICCs), coefficient of variation, and bias and limits of agreement were calculated for all variables. Results Mean results were similar between sessions 2 and 3 (P > .05). The relative reliability for the Sparta Science (ICC = 0.28-0.91) and biomechanical variables (ICC = 0.03-0.85) was poor to excellent. The mean absolute reliability (coefficient of variation) for Sparta Science variables was similar to or lower than that of the biomechanical variables during the CMJ (1-10% vs. 3-7%), one-leg balance (4-6% vs. 9-14%), and one-arm plank (5-7% vs. 12-17%) assessments. The mean bias for most variables was small (<5% of the mean), while the limits of agreement varied with most unacceptable (±6-87% of the mean). Conclusions The reliability of most Sparta Science and biomechanical variables during standard assessments was moderate to good. The typical variability in metrics documented will assist practitioners with the use of emerging technology to monitor and assess injury risk and/or training interventions in military personnel.

Impact of a 5-Week Individualised Training Program on Physical Performance and Measures Associated with Musculoskeletal Injury Risk in Army Personnel: A Pilot Study

“…After a 2 min rest, participants completed a two-leg CMJ, one-arm plank, one-leg balance and one-leg CMJ assessment without shoes (i.e., barefoot) using a commercially available and calibrated piezoelectric force plate, sampling at a frequency of 1000 Hz (Bertec/Sparta, SSFP01; Sparta Science, Menlo Park, CA, USA) [ 17 ]. All participants were instructed to perform each assessment to the best of their ability (i.e., maximal jump height, minimal movement during balance/plank).…”

“…Upon hearing an auditory cue that indicated stabilisation of body weight, participants performed a CMJ with 2-arm swing. Participants completed a total of four, maximal-effort two-leg CMJ with 15 s rest intervals provided between successive jumps [ 17 ]. A similar procedure was completed by participants during the last assessment of the session for one-leg CMJ assessments of both dominant and non-dominant legs.…”

“…The procedure was repeated on the left leg. During each balance test, participants were permitted to touch the ground with their elevated foot, if needed briefly, to maintain balance in accordance with the manufacturer’s protocols [ 17 ].…”

“…Pre-screening assessments, which aim to identify MSKI risk factors, are essential to inform the development and implementation of appropriate injury prevention programs [ 5 , 7 , 14 ]. The use of force plates [ 15 , 16 , 17 ] and computerised systems in the prevention of MSKI have been of interest recently in both sporting and military settings [ 1 , 15 , 18 ] with these technologies reported to be more reliable than traditional testing methods (e.g., Vertec jump test) in clarifying performance and identifying injury risk within a military setting [ 19 , 20 ]. One such system utilises a countermovement jump (CMJ) performance via force plates and proprietary software to identify imbalances that may exist (i.e., Sparta Science) [ 21 , 22 , 23 ].…”

“…One such system utilises a countermovement jump (CMJ) performance via force plates and proprietary software to identify imbalances that may exist (i.e., Sparta Science) [ 21 , 22 , 23 ]. Based on the CMJ outcomes, which have demonstrated moderate-to-excellent test–retest reliability in military personnel (ICC 0.67–0.91) [ 17 ], and implied imbalances, an individualised strength program is then recommended to improve these imbalances and decrease the risk of future MSKI [ 18 , 22 , 23 ]. To our knowledge, the effectiveness of an individualised and force plate guided program has not been examined in terms of feasibility, physical performance and changes in MSKI risk.…”