This dissertation was 2 parts of investigations of various acute responses to high-volume combined accentuated eccentric loading and rest redistribution (AEL + RR). Resistance-trained men (n = 12, 25.6 ± 4.4 years, 1.77 ± 0.06 m, 81.7 ± 11.4 kg) completed a back squat (BS) 1 repetition maximum (1RM) and weight releaser familiarization session. Three BS exercise conditions (sets × repetitions × eccentric/concentric loading) comprised AEL + RR 5: 3 × (5 × 2) × 110/60%, AEL + RR 2: 3 × (2 × 5) × 110/60%, and traditional sets (TS): 3 × (1 × 10) × 60/60% 1RM. The AEL + RR 5 resulted in significantly (p < 0.05) greater concentric peak velocity (PV) (1.18 ± 0.17 m∙s–1) and power (PP) (2,304 ± 499 W) compared to AEL + RR 2 (1.11 ± 0.19 m∙s–1 and 2,148 ± 512 W) and TS (1.10 ± 0.14 m∙s–1 and 2,079 ± 388 W). Furthermore, AEL + RR 5 resulted in significantly greater PV and PP across all 10 repetitions compared to TS. Although AEL + RR 5 resulted in significantly greater concentric mean force (MF) (1,706 ± 224 N) compared with AEL + RR 2 (1,697 ± 209 N) and TS (1,685 ± 211 N), no condition by set or repetition interactions were found. The AEL + RR 5 yielded greater total volume load (sets × repetitions × eccentric + concentric loading) (6630.1 ± 1210.4 kg) compared with AEL + RR 2 (5944.3 ± 1085.2 kg) and TS (5487.0 ± 1001.7 kg). The AEL + RR 5 led to significantly (p < 0.05) greater rating of perceived exertion (RPE) after set 2 and 3 and lower blood lactate (BL) after set 3, 5-, 15-, and 25-minute post-exercise than AEL + RR 2 and TS. There was a main effect of condition for BL between AEL + RR 5 (5.11 ± 2.90 mmol∙L–1), AEL + RR 2 (6.23 ± 3.22 mmol∙L–1), and TS (6.15 ± 3.17 mmol∙L–1). In summary, AEL + RR 5 results in unique acute mechanical, physiological, and perceptual responses in high-volume BS exercise.

Physiological adaptations were investigated following a strength-endurance (S-E) block prescribed with accentuated eccentric loading (AEL) or traditional resistance training (TRAD). Recreationally trained participants (n = 11 males, 6 females, age = 23.2 ± 4.2 yrs, body mass (BM) = 81.3 ± 22.2 kg, height = 172.1 ± 10 cm) completed a four-week block of concurrent resistance, sprint, and change of direction training. Participants were assigned one of two training conditions, AEL (n = 9) or TRAD (n = 8). Training was identical, except AEL performed 110% eccentric overloading every 1st, 3rd, 5th, 7th, and 9th repetition during back squat (BS) and bench press (BP). Body composition, summated muscle size (ACSAsum) and thickness (MTsum), regional ACSA and MT, and region-specific fascicle angle (FA) and length (FL) were assessed pre- (PRE) and post-training (POST). External work was calculated and exercise displacement was measured to determine the mechanical stimulus provided. Physiological variables were analyzed using multiple mixed analysis of variance (ANOVA). External work and displacement were analyzed with independent Welch’s t-tests. A statistically significant main effect of Time was observed for ACSAsum and ICW (p < 0.05); however, there were no statistically significant Time x Condition interaction effects observed for any dependent variable (p > 0.05). Time x Length interaction effects also failed to reach statistical significance for regional ACSA or regional MT (p > 0.05). Moreover, Time x Position interaction effects were not statistically significant for regional MT (p > 0.05). There were also no statistically significant interaction effects observed for regional FA or FL (p > 0.05). Differences in external work did not reach statistical significance (p > 0.05). A four-week S-E training block, performed with or without AEL, increases muscle size, but results in only minor architectural alterations. Additionally, AEL appears to induce unique region-specific hypertrophy. In contrast, TRAD seems to induce greater increases in ICW, potentially indicating greater sarcoplasmic hypertrophy. Interestingly, 110% eccentric overloading did not lead to statistically greater work performed, although differences may be practically significant when allometrically scaled. Researchers and practitioners should examine region-specific musculoskeletal adaptations, when possible, to more accurately assess training effects.