The purpose of this review was to provide a physiological rationale for the use of eccentric resistance training and to provide an overview of the most commonly prescribed eccentric training methods. Based on the existing literature, there is a strong physiological rationale for the incorporation of eccentric training into a training program for an individual seeking to maximize muscle size, strength, and power. Specific adaptations may include an increase in muscle cross-sectional area, force output, and fiber shortening velocities, all of which have the potential to benefit power production characteristics. Tempo eccentric training, flywheel inertial training, accentuated eccentric loading, and plyometric training are commonly implemented in applied contexts. These methods tend to involve different force absorption characteristics and thus, overload the muscle or musculotendinous unit in different ways during lengthening actions. For this reason, they may produce different magnitudes of improvement in hypertrophy, strength, and power. The constraints to which they are implemented can have a marked effect on the characteristics of force absorption and therefore, could affect the nature of the adaptive response. However, the versatility of the constraints when prescribing these methods mean that they can be effectively implemented to induce these adaptations within a variety of populations.

The purpose of this study was to determine the differences in kinetic, kinematic, and metabolic variables between an acute normal dead stop squat (NDS) protocol and an acute accentuated eccentric loaded squat (AEL) protocol. Eight collegiate weightlifters were performed the 2 squat protocols. Eccentric and concentric kinetic and kinematic data were collected via synchronized force plate and linear position transducer. Metabolic parameters assessed were oxygen consumption (VO2 ) using open circuit spirometry, testosterone (T) and cortisol (C) via blood draw from antecubital vein, and lactate (La) values via finger prick blood draw. The following are major findings of the dissertation. No statistical differences were observed for concentric variables between AEL and NDS work sets or between warm-up at 55% (WUP55) and postset at 55% (POST55) sets. Differences were found in the speed and duration of the eccentric portion of the lifts. Results indicate that there are no meaningful biomechanical differences when performing AEL squats in this manner and that the intensity and volume executed did not result in PAP. Oxygen uptake was statistically different during sets with the additional eccentric load (set 4, 5, 6, 7) and the subsequent down set (set 9). Lactate was greater during AEL squatting than NDS after set 7 and set 8 for the whole group. T exhibited no statistically significant changes. C was greater immediately following the AEL protocol compared to NDS 30 minutes post-AEL squat protocol yielded a statistically significant difference from immediately post and a return to near baseline measures. These acute changes may have meaningful effects on long- term gains in hypertrophy and strength. The findings of this dissertation show the potential benefits of AEL dead-stop squats for long-term hypertrophy and strength development. However, because this dissertation was the first to explore dead-stop squats with an additional eccentric load, further research is required on both the potential benefits of dead-stop squats and typical squats with no dead-stop using an AEL protocol.

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.

The purpose of this study was to investigate the chronic effects of accentuated eccentric loading (AEL) paired with cluster sets (CS) on dynamic and maximal strength, the endocrine system, and body composition. Seventeen recreationally active subjects (male = 11, females = 6, age = 23.05 ± 4.07, height = 172.09 ± 9.98, body mass = 81.29 ± 22.18, back squat to body mass ratio = 1.55 ± 0.33, bench press to body mass ratio = 1.06 ± 0.28) participated in one familiarization week, 2 weeks of testing, and 4 weeks of training. A strength-endurance block (4 wks) was used for training in which the target load consisted of 3 sets of 10 repetitions. The AEL group performed 3 sets of 10 repetitions for the squat and bench press using AEL every other repetition (5 AEL repetitions per set). Because of this protocol, CS were also performed as one AEL repetition plus one traditional repetition followed by 15 s rest. Weight releasers were attached during the rest between clusters. Resistance training was performed three days a week, sprint and agility work were performed two days a week. Maximum dynamic strength (1 RM squat, 1RM bench press), isometric maximum strength (Isometric midthigh pull) and rate of force development (RFD) were tested before and after the training protocol. Additionally, Testosterone (T), Cortisol (C), and Creatinine (CREA), fat mass (FM) and fat free mass (FFM) were assessed pre and post-test in 16 of the subjects as blood was unable to be collected from one of the subjects post test. Although maximum strength increased over time (n= 17), no statistically significant differences in strength occurred between the AEL and TRAD protocols after 4 weeks of training. No statistically significant differences in resting blood variables or body composition occurred between the AEL and TRAD protocols after 4 weeks of training.

The purpose of this review is to provide strength and conditioning practitioners with recommendations on how best to implement tempo eccentric training (TEMPO), flywheel inertial training (FIT), accentuated eccentric loading (AEL), and plyometric training (PT) into resistance training programs that seek to improve an athlete’s hypertrophy, strength, and power output. Based on the existing literature, TEMPO may be best implemented with weaker athletes to benefit positional strength and hypertrophy due to the time under tension. FIT may provide an effective hypertrophy, strength, and power stimulus for untrained and weaker individuals; however, stronger individuals may not receive the same eccentric (ECC) overload stimulus. Although AEL may be implemented throughout the training year to benefit hypertrophy, strength, and power output, this strategy is better suited for stronger individuals. When weaker and stronger individuals are exposed to PT, they are exposed to an ECC overload stimulus as a result of increases in the ECC force and ECC rate of force development. In conclusion, when choosing to utilize ECC training methods, the practitioner must integrate these methods into a holistic training program that is designed to improve the athlete’s performance capacity.