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HomeSport and Exercise MedicineResistance training: Lower more than you lift

Resistance training: Lower more than you lift

Two recent studies show that greater benefits occur when lowering (eccentric) a greater load than is lifted (concentric) during resistance-training.

Individuals that trained with accentuated eccentric loads gained more strength and they showed greater increases in blood hormone concentration compared to those who used the same load for both lowering and lifting phases (traditional resistance-training).

"Humans have a greater ability to produce force when lowering (eccentric) a load compared to lifting (concentric). So it seems logical to train with greater eccentric loads than those used during the concentric phase of the lift. Unfortunately, this does not happen in traditional resistance-training," says Dr Simon Walker from the University of Jyväskylä.

Resistance-trainers gained benefit to their maximum eccentric strength, as well as their strength-endurance in their legs. This was especially evident in the second half of the training period. Accompanying the divergent performance improvements, the accentuated eccentric group demonstrated large increases in hormone concentrations during the training session in week-9 while the traditional resistance-training group showed a much lower response.

"Chronic resistance-training using the same methods will lead to a plateau in performance gains. It seems that using accentuated eccentric loads provided a greater stimulus for our trainers. The hormone results suggest that the strenuousness imposed by the training stimulus continued for a longer period of time. This likely explains why gains in strength stopped at 5 weeks in those using traditional resistance-training methods, while the accentuated eccentric group continued to improve over 10 weeks," Walker explains.

The improvements in strength were most likely due to a greater mental effort to control the lowering of the heavy loads, since both groups increased thigh muscle mass similarly but only the accentuated eccentric group improved their ability to maximally activate the leg muscles.

Abstract 1
As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading vs. traditional isoinertial resistance training in strength-trained men. Young (22 ± 3 years, 177 ± 6 cm, 76 ± 10 kg, n = 28) strength-trained men (2.6 ± 2.2 years experience) were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%) or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle) and isokinetic (concentric and eccentric 30°.s−1) knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasonography and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18 ± 10 vs. 1 ± 5%, p < 0.01), which was accompanied by an increase in voluntary activation (3.5 ± 5%, p < 0.05). Isokinetic eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p < 0.05), whereas concentric torque increased equally in both the accentuated eccentric load (10 ± 9%, p < 0.01) and traditional (9 ± 6%, p < 0.01) resistance training groups; however, the increase in the accentuated eccentric load group was significantly greater (p < 0.05) than control (1 ± 7%). Knee extension repetition-to-failure improved in the accentuated eccentric load group only (28%, p < 0.05). Similar increases in muscle mass occurred in both intervention groups. In summary, accentuated eccentric load training led to greater increases in maximum force production, work capacity and muscle activation, but not muscle hypertrophy, in strength-trained individuals.

Authors
Simon Walker, Anthony J Blazevich, G Gregory Haff, James J Tufano, Robert U Newton, Keijo Häkkinen

Abstract 2
It has been proposed that the maintenance of acute hormonal responses reveal an efficacy of a training stimulus to evoke ongoing increases in strength and muscle mass. We previously observed that maximum strength continued to improve throughout a 10‐week period in an accentuated eccentric loading group (AEL) but not a traditional isoinertial loading (ISO) group. Therefore, this study investigated whether the magnitude of acute hormonal responses was greater (i.e., maintained) in AEL compared to ISO at the end of the training period. Subjects in AEL (eccentric load = concentric load + 40%) and ISO performed experimental loading tests (three sets of 10 repetitions in the leg press and knee extension exercises) during weeks 2 and 9 of the training period. Blood samples collected during these experimental loadings were analyzed for serum testosterone, growth hormone and cortisol concentrations. Maximum isometric knee extension torque (MVC) and lower‐limb lean mass were assessed before and after 5 and 10 weeks of training. Acute testosterone, growth hormone and cortisol responses to traditional isoinertial loading were reduced at the end of the training period but were not reduced after accentuated eccentric load training (P < 0.05‒0.1 between‐groups). Increases in MVC and lower‐limb lean mass over weeks 6‒10 were greater in AEL compared to ISO (MVC: 7.3 ± 5.4 vs. −0.4 ± 7.2%, P = 0.026 for between‐group difference; lower‐limb lean mass: 1.6 ± 2.2 vs. −0.2 ± 1.4%, P = 0.063 for between‐group difference). The maintenance of acute hormonal responses and continued strength gain in AEL but not ISO are consistent with the hypothesis that maintained acute responses indicate an efficacy of a training stimulus to evoke ongoing adaptation. However, since relationships between hormonal responses and training‐induced adaptations were not statistically significant, the data suggest that tracking of acute hormonal responses on an individual level may not provide a sensitive enough guide for decisions regarding program design and periodization.

Authors
Simon Walker, Keijo Häkkinen, Guy Gregory Haff, Anthony J Blazevich, Robert U Newton

[link url="https://www.sciencedaily.com/releases/2017/05/170502084532.htm"]University of Jyväskylä material[/link]
[link url="http://journal.frontiersin.org/article/10.3389/fphys.2016.00149/full"]Frontiers in Physiology abstract[/link]
[link url="http://physreports.physiology.org/content/5/7/e13241"]Physiological Reports abstract[/link]

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