While current research offers evidence-based strength training approaches to enhance endurance running performance, numerous popular strength training models have not been empirically tested in this context.
PURPOSE: Compare the effects of periodized lower body strength training versus high intensity circuit strength training on running performance and related variables in experienced runners.
METHODS: Participants (N = 19) were randomized to 8 weeks of periodized lower body strength training (PLB), n = 9, or high intensity circuit training (CT), n = 10. All participants strength trained 2 d·wk-1 and followed their typical running schedule. PLB sessions included 2 sets of the back squat, standing calf raise, leg press, and dumbbell lunge, with intensity linearly periodized. PLB initially completed sets at 10-repetition maximum (10-RM) and progressed each 2 weeks to 8-RM, 6-RM, and 4-RM. CT sessions included a high intensity, whole body resistance circuit followed by 2-4 heavy (>10-RM) sets of a compound lift, simulating CrossFit©-style programming. 3-km time trial (TT), VO2 max, relative leg press 1-RM, running economy (RE) at 2 standard submaximal velocities (SV1, SV2) between 11 and 14 km·hr-1, RPE at SV1/SV2, and peak/mean power during the Wingate Anaerobic Test were assessed pre and post-intervention.
RESULTS: Two-way ANOVA showed a significant main effect of time on RE at 11 km·hr-1 (F = 8.31, p = .02, ηp2 = 0.51) and RPE at SV1 (F = 11.2, p = .004, ηp2 = .40), and a significant group*time interaction on 1-RM (F = 7.66, p = .015, ηp2 = .35) and RPE at SV2 (F = 5.30, p = .037, ηp2 = .28). Similar (p ≤ .02) increases occurred in RE at 11 km·hr-1 (36.4 ± 3.1 to 35.4 ± 2.4 ml·kg-1·min-1) and RPE at SV 1 (12.5 ± 1.3 to 11.4 ± 1.6). Relative 1-RM (2.54 ± 0.41 to 3.40 ± 0.72) and RPE at SV2 (14.1 ± 1.3 to 12.9 ± 1.8) improved in both groups (p ≤ .03). However, PLB showed larger improvements in 1-RM (0.43 ± 0.18 vs. 0.2 ± 1.9, t = 2.75, p = .015) and RPE at SV2 (-1.75 ± 0.9 vs. -0.63 ± 1.1, t = 2.30, p = .037). TT, VO2 max, RE at 12-14 km·hr-1, and power were unchanged (p ≥ .27).
CONCLUSIONS: Both modalities enhanced lower body strength, RE at 11 km·hr-1 and submaximal RPE at submaximal, but neither improved TT performance, VO2 max, power, or RE at faster velocities. PLB resulted in greater improvements in lower body strength and RPE at higher submaximal running velocity.