The purpose of this study was to compare the effects of intra-set rest intervals (ALT) and traditional resistance (STD) training in hypertrophic resistance training. 22 males (25 +/- 5yrs, 179.71 +/- 5.0cm, 82.1 +/- 10.6kg, 13.6 +/- 4.3% fat, 6.5 +/- 4.5yrs training) were matched according to baseline characteristics and randomly assigned to a STD or ALT 12 week hypertrophic training protocol. Body composition, strength (1RM bench and squat); power (60% 1RM bench and squat); and vertical jump were assessed at baseline, 4, 8, and 12 weeks. Muscle biopsy for myosin heavy chain (MHC) was performed pre and post training. A 2 x 4 (Group x Time) ANOVA was used to assess changes in body composition. A 2 x 4 (Group x Time) ANCOVA covaried by baseline performance measures was used to assess differences in strength and power characteristics. A 2 x 2 (Group x Time) ANCOVA covaried for baseline percentage MHC was used to determine differences pre and post training. Both groups experienced increases in FFM with no differences between groups (62.6 +/- 7.9, 63.4 +/- 7.6, 64.2 +/- 7.4, 64.2 +/- 7.5kg; p>0.05). No time effects were noted in percent fat (13.6 +/- 4.3, 14.1 +/- 4.7, 14.0 +/- 4.6, 14.3 +/- 4.6%fat; p>0.05). Increase in FFM was associated with a decrease in MHCIIX, (ALT, -37.9 +/- 24.1%; STD, -23.4 +/- 23.8%; p = 0.001) and an increase in MHCIIA (ALT, 32.0 +/- 28.8%; STD, 25.4 +/- 29.1%; p = 0.001) with no difference between groups. A significant interaction was observed with the ALT group experiencing greater gains in both 1RM bench (STD 104.1 +/- 27.6, 102.7 +/- 29.0, 107.0 +/- 25.3, 113.2 +/- 27.3; ALT 110.9 +/- 20.1, 117.5 +/- 23.7, 120.8 +/- 22.6, 126 +/- 22.8; p<0.05) and 1RM squat (STD 123.3 +/- 39.3, 139.6 +/- 38.8, 160.2 +/- 36.1, 171.8 +/- 34.5; ALT 130.1 +/- 25.1, 152.6 +/- 24.8, 179.8 +/- 24.5, 193.9 +/- 24.2kg; p<0.05). The ALT group experienced greater gains in power in both the bench (STD 560 +/- 122, 541 +/- 105, 572 +/- 122, 593 +/- 135W; ALT 575 +/- 102, 586 +/- 123, 646 +/- 103, 658 +/- 113W; p<0.05) and vertical jump (STD 1378 +/- 237, 1418 +/- 214, 1452 +/- 210, 1470 +/- 215W; ALT 1389 +/- 179, 1434 +/- 152, 1470 +/- 149, 1537 +/- 150W;p<0.05), with gains in squat power approaching significance (STD 625 +/- 245, 704 +/- 233, 723 +/- 227, 830 +/- 232W; ALT 632 +/- 171, 734 +/- 179, 783 +/- 188, 914 +/- 207W; p<0.10). The use of intra-set rest intervals in programs designed to elicit hypertrophy results in greater gains in strength and power with no significant difference in lean mass or MHC composition after a 12 week resistance training program designed to elicit hypertrophy.

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.