Influence Of Interval-based Resistance Training On Dynamic Balance Performance In Active-duty Firefighters

Firefighter (FF) injuries largely occur from overexertion and balance-related falls, slips, and trips. Interval-based resistance training (IRT) may support FF fitness for duty and simultaneously enhance balance performance due to links to body composition and strength. PURPOSE: The purpose of this study was to the examine the influence of IRT on dynamic balance performance in active-duty FFs. METHODS: FFs were randomly assigned to control (CTL; n = 14, 1 female, 38.64 ± 9.36 yrs, 91.79 ± 16.53 kg, 178.84 ± 4.11 cm) or training intervention (TR; n = 13, 1 female, 33.31 ± 7.15 yrs, 89.80 ± 11.60 kg, 179.75 ± 7.03 cm) groups. For 8-weeks, CTLs maintained their current regimen and TRs completed full-body IRT twice weekly. Before (PRE) and after (POST) the intervention, assessments were measured including: body weight (BW, kg), height (HT, cm), percent body fat (BF, %) via skinfolds, muscular strength from the sum of right and left handgrip (kg) normalized to BW (HG, kg/kg), and dynamic balance by quickly walking down and back on a narrow plank with an overhead obstacle at 75% of their HT. Each trial (sec) was summed with added time for minor (i.e., loss of balance; +1 sec) and major (i.e., contact with obstacle that falls away; +2 sec) errors and averaged into a performance index (PI). A 2 x 2 (TIME x GROUP) repeated measures analysis of covariance (RM ANCOVA) examined the influence of training on PI when controlling for age. Partial correlations examined relationships between PI and BF and HG changes (Δ) when controlling for age. An alpha of .05 determined statistical significance. RESULTS: When controlling for age, a non-significant RM ANCOVA interaction was identified (F1,24 = .374, P = .547). Non-significant main effects were identified for GROUP (F1,24 = .184, P = .671; mean ± SE; PICTL 6.145 ± .473 = PITR 5.844 ± .492) and TIME (F1,24 = .566, P = .459; PIPRE 6.357 ± .307 = PIPOST 5.632 ± .402). When controlling for age, non-significant relationships were identified between PIΔ (mean ± SD; -.719 ± 1.325) and BFΔ (r = -.072, P = .727; -1.518 ± 2.50 %) and HGΔ (r = -.064, P = .756; -.008 ± .147 kg/kg). CONCLUSIONS: IRT did not enhance dynamic balance, nor was performance related to body composition or strength changes. Future research should examine if results are similar following IRT at a higher dose or when including more balance-specific exercises.