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Journal ArticleDOI

An Evaluation of Supramaximally Loaded Eccentric Leg Press Exercise

20 Feb 2018-Journal of Strength and Conditioning Research (J Strength Cond Res)-Vol. 32, Iss: 10, pp 2708-2714

TL;DR: The information gathered in the study provides a foundation for practitioners to consider when devising loading strategies and implementing or evaluating supramaximally loaded eccentric exercise when using a similar exercise and device.

AbstractHarden, M, Wolf, A, Russell, M, Hicks, KM, French, D, and Howatson, G. An evaluation of supramaximally loaded eccentric leg press exercise. J Strength Cond Res 32(10): 2708-2714, 2018-High-intensity eccentric exercise is a potent stimulus for neuromuscular adaptation. A greater understanding of the mechanical stimuli afforded by this exercise will aid the prescription of future eccentric training regimens. This study sought to investigate the mechanical characteristics of supramaximally loaded eccentric exercise when using a custom-built leg press machine. Using a within-subject, repeated-measures design, 15 strength trained subjects (age, 31 ± 7 years; height, 180.0 ± 6.8 cm; body mass, 81.5 ± 13.9 kg) were assessed under 3 different conditions: low (LO), moderate (MOD), and high (HI) intensity, which were equivalent in intensity to 110, 130, and 150%, respectively, of peak force during an isometric maximal voluntary contraction (IMVC) performed on leg press at 90° knee flexion. All loading conditions demonstrated a similar pattern of mechanical profile; however, the variables underpinning each profile showed significant (p < 0.01) load-dependent response (LO vs. MOD, MOD vs. HI, LO vs. HI) for all variables, except for average acceleration. Average force associated with each loading conditions exceeded IMVC but equated to a lower intensity than what was prescribed. Repetitions under higher relative load intensity stimulated greater average force output, faster descent velocity, greater magnitude of acceleration, shorter time under tension, and a decline in force output at the end range of motion. This research provides new data regarding the fundamental mechanical characteristics underpinning supramaximally loaded eccentric leg press exercise. The information gathered in the study provides a foundation for practitioners to consider when devising loading strategies and implementing or evaluating supramaximally loaded eccentric exercise when using a similar exercise and device.

Topics: Leg press (60%), Eccentric training (57%), Eccentric (54%), Isometric exercise (54%)

Summary (3 min read)

INTRODUCTION

  • Eccentric resistance exercise classically involves resisting an external load during the descending phase of an exercise movement.
  • Modification and instrumentation of the inclined leg press device removed the potential limitations associated with high intensity eccentric training practice, such that it was possible to apply very high loads eccentrically and allow an investigation of the fundamental mechanics associated with this mode of exercise.
  • The range of intensities were chosen to ensure that manipulation in external load (independent variable, IV) was sufficiently different enough to produce mechanical differences in the kinetic and kinematic parameters (dependent variable, DV).
  • A smaller intensity range may have produced similar data across conditions thus making it difficult to draw meaningful conclusions for coaching and research practice.

Subjects

  • All subjects were from a strength-power sport background e.g., Olympic weightlifting, rugby, athletics and track sprint cycling, with 11 ± 7 years of resistance training experience, which had included phases of maximum strength training.
  • All subjects were free from musculoskeletal injury for at least 12 months before the study started, and reported no musculoskeletal or cardiovascular disorders.
  • The volunteers were required to avoid unaccustomed exercise during the whole study period, refrain from strenuous exercise in the 48 hours prior to attending each testing and were instructed to attend each session in a well-hydrated and fed state, having abstained from alcohol in the preceding 24 hours.
  • Subjects were informed of the benefits and risks associated with the investigation, as well as all study procedures prior to providing written, informed consent.
  • The study procedures and consent documentation was approved by University Ethics Committee in accordance with The Declaration of Helsinki.

Procedures

  • The custom-built 45° incline leg press machine (Sportesse, Somerset, UK) facilitates performance and assessment of concentric, isometric and eccentric exercise .
  • The isometric function of the leg press operates via an inbuilt locking mechanism that can secure the carriage at any position along the machines framework.
  • The load cells and potentiometers sampled at 200 Hz.
  • Securing the leg press carriage at 90° of the subjects’ knee flexion (verified by goniometry), they completed 3 x 1 repetition at each of the following perceived intensities; 50%, 75% and 100% for 3 seconds per repetition.
  • Preceding the LO trial an additional 1 repetition with an external load equivalent to 100% IMVC was completed, preceding the MOD trial an additional 1 repetition with an external load equivalent to 110% IMVC was completed, and preceding the HI trial an additional 1 repetition with an external load equivalent to 130% IMVC was completed.

Statistical Analyses

  • Intraclass correlation coefficients (ICC) and coefficients of variation (CV, %) including 95% confidence intervals were calculated to determine the repeatability of eccentric performances between 2 repetitions (7).
  • Using SPSS (Version 24.0; SPSS Inc, Chicago, USA) a repeated measures ANOVA was used to determine significant differences in the DV’s; force (average and end), TUT, velocity and acceleration between each loading condition (IV) and where appropriate, a Bonferroni post-hoc test.
  • Group data are presented as mean ± SD with 95% confidence intervals (CI).

RESULTS

  • Average force associated with each loading conditions exceeded IMVC peak force but was less than the prescribed external force.
  • All loading conditions demonstrated a similar pattern of mechanical profile , however, the variables underpinning each profile showed significant (p < 0.01) load dependent response (LO vs MOD, MOD vs HI, LO vs HI) for all variables, except for average acceleration which was significantly different between LO and HI, only (p = 0.05) (Table 1).
  • Force at the end ROM was 1%, 3% and 5% less than the average force measured over the ROM for LO, MOD and HI trials respectively.

DISCUSSION

  • The aim of this research was to investigate the fundamental mechanical characteristics associated with supramaximal intensity eccentric leg press exercise.
  • The results showed that the heavier relative external load stimulated greater average force output which, in turn, was associated with a faster descent velocity and shorter TUT.
  • Because of this, the intensity of the supramaximal load was less than the prescribed 110, 130 and 150% relative to peak force exerted during the IMVC.
  • To understand the acute and chronic responses to this type of eccentric exercise and the different force-TUT interactions more research is warranted, particularly given the growing interest in elite sport to maximize adaptation from eccentric loading.
  • This would enable practitioners to accurately determine an individual’s eccentric force producing capacity and prescribe eccentric training more accurately.

PRACTICAL APPLICATIONS

  • Overall, supramaximally loaded eccentric-only exercise appears to offer a unique and potent stimulus; individuals can be exposed to extended TUT at high levels of force that exceed what more traditional regimes might offer.
  • When implementing supramaximal loaded eccentric-only repetitions, practitioners should be mindful to prescribe a load that is well tolerated in the restricted portion (end ROM) of the exercise movement to facilitate continued force production and maintenance of muscular tension for sustained and consistent movement.
  • This study has addressed the acute mechanical response to supramaximally loaded eccentric-only exercise under different magnitudes of external load.
  • As the experimental approach was devised with practical application in mind, the results provide strength coaches and applied practitioners with a greater understanding of the mechanical demand imposed by supramaximally loaded eccentric-only leg press exercise.
  • Importantly, these data provide new insight into the performance response from strength-trained individuals throughout supramaximal eccentric leg press exercise.

Author contributions

  • MH, DF, MR, GH, also known as Experiment planning and design.
  • Data collection: MH. Data Analysis: MH, GH.
  • MH, GH, AW, KH, also known as Interpreted results of research.

Figure Legends

  • Table 1. Mechanical characteristics of eccentric leg press repetitions during LO, MOD and HI intensity loading conditions Figure 1.
  • Incline leg press with; (A) unilateral force plates, (B) air compression unit, (C) removable steel bar insert, (D) safety pins, (E) adjustable seat.
  • Underneath the foot carriage; (F) adjustable ROM sensors, also known as Right photo.
  • A representative mechanical profile for a single eccentric leg press repetition under three supramaximal loading conditions.
  • Black solid line: LO intensity loading condition, dark grey solid line: MOD intensity loading condition, light grey solid line:.

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1
JSCR-08-10057 R1
AN EVALUATION OF SUPRAMAXIMALLY LOADED ECCENTRIC LEG PRESS
EXERCISE

2

3
AN EVALUATION OF SUPRAMAXIMALLY LOADED ECCENTRIC LEG PRESS
EXERCISE
Running title: Mechanical characteristics of eccentric exercise
Mellissa Harden
1,2
, Alex Wolf
2
, Mark Russell
5
, Kirsty M Hicks
1
, Duncan French
4
, Glyn
Howatson
1,3
1
Department of Sport Exercise and Rehabilitation, Faculty of Health and Life Sciences,
Northumbria University, UK
2
English Institute of Sport, UK
3
Water Research Group, School of Environmental Sciences and Development, Northwest
University, Potchefstroom, South Africa
4
UFC Performance Institute, USA
5
School of Social and Health Sciences, Leeds Trinity University, Leeds, UK
Corresponding author:
Glyn Howatson, PhD
Department of Sport, Exercise and Rehabilitation
Faculty of Health and Life Sciences
Northumbria University
Newcastle upon Tyne, UK
Tel: +44 (0) 191 227 3575
Email: glyn.howatson@northumbria.ac.uk
Funding: This work was completed under a joint funded doctoral studentship between the
English Institute of Sport and Northumbria University.
Laboratory: HSBC National Cycling Centre, English Institute of Sport, Manchester, UK

4
ABSTRACT
High intensity eccentric exercise is a potent stimulus for neuromuscular adaptation. A greater
understanding of the mechanical stimuli afforded by this exercise will aid the prescription of future
eccentric training regimes. This study sought to investigate the mechanical characteristics of
supramaximally loaded eccentric exercise when using a custom-built leg press machine. Using a
within subject, repeated measures design, 15 strength trained subjects (age 31 ± 7 years; height
180.0 ± 6.8 cm; body mass 81.5 ± 13.9 kg) were assessed under three different conditions; LO,
MOD and HI which were equivalent in intensity to 110, 130 and 150%, respectively, of peak force
during an isometric leg-press at 90° knee flexion (IMVC). All loading conditions demonstrated a
similar pattern of mechanical profile, however, the variables underpinning each profile showed
significant (p < 0.01) load dependent response (LO vs MOD, MOD vs HI, LO vs HI) for all
variables, except for average acceleration. Average force associated with each loading conditions
exceeded IMVC, but equated to a lower intensity than what was prescribed. Repetitions under
higher relative load intensity stimulated greater average force output, faster descent velocity,
greater magnitude of acceleration, shorter TUT and a decline in force output at the end range of
motion. This research provides new data regarding the fundamental mechanical characteristics
underpinning supramaximally loaded eccentric leg press exercise. The information gathered in
the study provides a foundation for practitioners to consider when devising loading strategies, and
implementing or evaluating supramaximally loaded eccentric exercise when using a similar
exercise and device.
Keywords: maximal force, load prescription, muscle lengthening

Citations
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Abstract: Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training programmes have also been provided to show how these can be addressed.

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TL;DR: The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased.
Abstract: The aim of this study was to analyze the literature on muscle activation measured by surface electromyography (sEMG) of the muscles recruited when performing the leg press exercise and its variants The Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to report this review The search was carried out using the PubMed, Scopus, and Web of Science electronic databases The articles selected met the following inclusion criteria: (a) a cross-sectional or longitudinal study design; (b) neuromuscular activation assessed during the leg press exercise, or its variants; (c) muscle activation data collected using sEMG; and (d) study samples comprising healthy and trained participants The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased In conclusion, (1) the vastus lateralis and vastus medialis elicited the greatest muscle activation during the leg press exercise, followed closely by the rectus femoris; (2) the biceps femoris and the gastrocnemius medialis showed greater muscular activity as the knee reached full extension, whereas the vastus lateralis and medialis, the rectus femoris, and the tibialis anterior showed a decreasing muscular activity pattern as the knee reached full extension; (3) evidence on the influence of kinematics modifications over sEMG during leg press variants is still not compelling as very few studies match their findings

4 citations


Journal ArticleDOI
TL;DR: AEL is sensitive to the magnitude of concentric loads, which requires a large relative difference to the eccentric load, and weight releasers may not need to be reloaded to induce performance enhancement.
Abstract: PURPOSE To identify acute effects of a single accentuated eccentric loading (AEL) repetition on subsequent back-squat kinetics and kinematics with different concentric loads. METHODS Resistance-trained men (N = 21) participated in a counterbalanced crossover design and completed 4 protocols (sets × repetitions at eccentric/concentric) as follows: AEL65, 3 × 5 at 120%/65% 1-repetition maximum (1-RM); AEL80, 3 × 3 at 120%/80% 1-RM; TRA65, 3 × 5 at 65%/65% 1-RM; and TRA80, 3 × 3 at 80%/80% 1-RM. During AEL, weight releasers disengaged from the barbell after the eccentric phase of the first repetition and remained off for the remaining repetitions. All repetitions were performed on a force plate with linear position transducers attached to the barbell, from which eccentric and concentric peak and mean velocity, force, and power were derived. RESULTS Eccentric peak velocity (-0.076 [0.124] m·s-1; P = .01), concentric peak force (187.8 [284.4] N; P = .01), eccentric mean power (-145.2 [62.0] W; P = .03), and eccentric peak power (-328.6 [93.7] W; P < .01) during AEL65 were significantly greater than TRA65. When collapsed across repetitions, AEL65 resulted in slower eccentric velocity and power during repetition 1 but faster eccentric and concentric velocity and power in subsequent repetitions (P ≤ .04). When comparing AEL80 with TRA80, concentric peak force (133.8 [56.9] N; P = .03), eccentric mean power (-83.57 [38.0] W; P = .04), and eccentric peak power (-242.84 [67.3] W; P < .01) were enhanced. CONCLUSIONS Including a single supramaximal eccentric phase of 120% 1-RM increased subsequent velocity and power with concentric loads of 65% 1-RM, but not 80% 1-RM. Therefore, AEL is sensitive to the magnitude of concentric loads, which requires a large relative difference to the eccentric load, and weight releasers may not need to be reloaded to induce performance enhancement.

3 citations


Journal ArticleDOI
29 Jul 2020-PLOS ONE
TL;DR: The eccentric leg press stimulus was well-tolerated, supporting the inclusion of such training in the preparation programmes of athletes.
Abstract: This study assessed the efficacy of strength training using augmented eccentric loading to provoke increases in leg strength in well-trained athletes, and sprint track cyclists, using a novel leg press device. Twelve well-trained athletes were randomly allocated traditional resistance training (TRAD, n = 6), or resistance training using augmented eccentric loading (AEL, n = 6). A further 5 full-time, professional sprint track cyclists from a senior national squad programme also trained with augmented eccentric loading (AEL-ATH) alongside their usual sport-specific training. Participants completed four weeks of twice-weekly resistance training using the leg press exercise. In TRAD the lowering phase of the lift was set relative to concentric strength. In AEL and AEL-ATH the lowering phase was individualised to eccentric strength. Concentric, eccentric, isometric and coupled eccentric-concentric leg press strength, and back squat 1 repetition maximum (1RM), were assessed pre- and post-training. The AEL and AEL-ATH groups performed the eccentric phase with an average 26 ± 4% greater load across the programme. All groups experienced increases in concentric (5%, 7% and 3% for TRAD, AEL & AEL-ATH respectively), eccentric (7%, 11% and 6% for TRAD, AEL & AEL-ATH respectively), and squat 1RM (all p < 0.05), where the AEL-ATH group experienced relatively greater increases (13% vs. 5% in TRAD and AEL, p < 0.01). The TRAD and AEL groups also increased isometric strength (p < 0.05). A four-week period of augmented eccentric loading increased leg strength in well-trained athletes and track cyclists. The eccentric leg press stimulus was well-tolerated, supporting the inclusion of such training in the preparation programmes of athletes.

3 citations


Cites background or methods from "An Evaluation of Supramaximally Loa..."

  • ...The bespoke leg press has been previously described [18, 19]....

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  • ...Our previous work has established the reliability of this stimulus [18], and its mechanical characteristics [19], as a foundation on which to prescribe training....

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  • ...To this end, we have developed a novel leg press device capable of overloading eccentric muscle action in a lower body, bilateral, multi-joint movement [18, 19]....

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Dissertation
01 Oct 2018
TL;DR: There is evidence in this thesis to support the potency of eccentric cycling as a mechanical training stimulus, the consequences of different session structures, and the ease at which it can be added to the training program of well-trained runners.
Abstract: Eccentric cycling is an emerging exercise modality in which an individual resists pedals being driven towards them on a motorised recumbent cycle ergometer. The attractiveness of eccentric cycling as a training modality stems, at least in part, from its propensity to elicit greater levels of mechanical tension for a lower metabolic cost compared to predominantly concentric or isometric training modalities. The aim of this thesis was to systematically investigate the neuromuscular responses and application to athletic performance of a bespoke eccentric cycling instrument. Study 1 assessed the reproducibility of torque, power, and muscle activation during maximal eccentric cycling over a range of cadences. This study demonstrated that at least one familiarisation session should be employed to account for the initial learning effect, although, generally poor between-session reliability was observed. A cadence of 60 rpm displayed the greatest reliability thus highlighting it as a preferential choice for use in future work. Study 2 compared the mechanical stress of, and muscle activation responses to, maximal eccentric and concentric cycling over a range of cadences. Eccentric cycling elicited up to 2.1 times greater torque and power compared to concentric cycling. Additionally, markers of technique e.g. pedal angle of peak muscle activation, and peak torque, also varied between modalities. Study 3 compared the immediate and delayed (up to 72 h post) responses to work-matched interval and continuous eccentric cycling. Decrements in muscle function (31% vs. 18%), and recovery time (48 vs. 24 hrs) were greater after the interval session; a finding attributed to greater peak mechanical tension. This greater mechanical potency of interval eccentric cycling provided rationale for its use over a longer period of training. In study 4 (a pilot study) the effects of an 8-week interval eccentric cycling intervention was examined in well trained distance runners. There was a limited effect on running economy, stretch shortening cycle function, and strength, however, data indicated a possible effect on eccentric strength and jump performance which warrants further investigation. Eccentric cycling does not appear to impact upon well trained athletes to the extent previously observed in untrained or physically impaired populations. Although, there is evidence in this thesis to support the potency of eccentric cycling as a mechanical training stimulus, the consequences of different session structures, and the ease at which it can be added to the training program of well-trained runners.

2 citations


References
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Journal ArticleDOI
TL;DR: The possibility that voluntary muscle lengthening contractions can be performed by selective recruitment of fast‐twitch motor units, accompanied by derecruitment of slow‐ twitch motor units is investigated.
Abstract: 1. We have investigated the possibility that voluntary muscle lengthening contractions can be performed by selective recruitment of fast-twitch motor units, accompanied by derecruitment of slow-twitch motor units. 2. The behaviour of motor units in soleus, gastrocnemius lateralis and gastrocnemius medialis muscles was studied during (a) controlled isotonic plantar flexion against a constant load (shortening contraction, S), maintained plantar flexion, or dorsal flexion resisting the load and gradually yielding to it (lengthening contraction, L), (b) isometric increasing or decreasing plantar torque accomplished by graded contraction or relaxation of the triceps surae muscles, (c) isometric or isotonic ballistic contractions, and (d) periodic, quasi-sinusoidal isotonic contractions at different velocities. The above tasks were performed under visual control of foot position, without activation of antagonist muscles. The motor units discharging during foot rotation were grouped on the basis of the phase(s) during which they were active as S, S + L and L. The units were also characterized according to both the level of isometric ramp plantar torque at which they were first recruited and the amplitude of their action potential. 3. S units were never active during dorsal flexion; some of them were active during the sustained contraction between plantar and dorsal flexion. Most S + L units were active also during the maintenance phase and were slowly derecruited during lengthening; their behaviour during foot rotations was similar to that during isometric contractions or relaxations. L units were never active during either plantar or maintained flexion, but discharged during lengthening contraction in a given range of rotation velocities; the velocity of lengthening consistently influenced the firing frequency of these units. Such dependence on velocity was not observed in S + L units. 4. A correlation was found between the amplitude of the action potential and the threshold torque of recruitment among all the units. In addition, the amplitudes of both the action potential and the threshold torque were higher in the case of L units than in the case of S and S + L units. Most L units could be voluntarily recruited only in the case of ballistic isometric or isotonic contraction. 5. Occasionally, L units were directly activated by electrical stimulation of motor fibres and their conduction velocity was in the higher range for alpha-axons. In contrast, nerve stimulation could induce a reflex activation of S and S + L units.(ABSTRACT TRUNCATED AT 400 WORDS)

653 citations


"An Evaluation of Supramaximally Loa..." refers background in this paper

  • ...There is a wealth of evidence to suggest that following habitual use of high intensity eccentric exercise there is an increase in muscle cross-sectional area and morphological alterations of muscle architecture (2), preferential recruitment of type II muscle fibers (13), increase in isometric and concentric force (3,9,10), enhanced task specific gains in eccentric strength (10), reduced neural inhibition and increase in muscle activation (1,17)....

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Journal ArticleDOI
Roger M. Enoka1
TL;DR: This review examines the experimental evidence that provides the foundation for the current understanding of the benefits, consequences, and control of eccentric contractions and suggests a new hypothesis: that the neural commands controlling eccentric contraction are unique.
Abstract: Enoka, Roger M. Eccentric contractions require unique activation strategies by the nervous system. J. Appl. Physiol. 81(6): 2339–2346, 1996.—Eccentric contractions occur when activated muscles are ...

618 citations


"An Evaluation of Supramaximally Loa..." refers background in this paper

  • ...This could be expected given that that neural control strategies during eccentric and isometric actions are different (4)....

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Journal ArticleDOI
TL;DR: Ecc is more effective than Con isokinetics training for developing strength in Ecc isokinetic muscle actions and that Con is moreeffective than Ecc iskinetic training fordeveloping strength in Con iskinetics muscle actions.
Abstract: Higbie, Elizabeth J., Kirk J. Cureton, Gordon L. Warren III, and Barry M. Prior. Effects of concentric and eccentric training on muscle strength, cross-sectional area, and neural activation.J. Appl...

452 citations


"An Evaluation of Supramaximally Loa..." refers background in this paper

  • ...This eccentric-only movement has minimal involvement of the stretchshortening cycle (SSC) (5), and the slow nature of this exercise perhaps lacks task-specificity to some sports (18)....

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Journal ArticleDOI
TL;DR: It is concluded that adaptations to training with maximal eccentric contractions are specific to eccentric muscle actions that are associated with greater neural adaptation and muscle hypertrophy than concentric exercise.
Abstract: We tested the hypothesis that exercise training with maximal eccentric (lengthening) muscle actions results in greater gains in muscle strength and size than training with concentric (shortening) a...

409 citations


"An Evaluation of Supramaximally Loa..." refers background in this paper

  • ...There is a wealth of evidence to suggest that following habitual use of high intensity eccentric exercise there is an increase in muscle cross-sectional area and morphological alterations of muscle architecture (2), preferential recruitment of type II muscle fibers (13), increase in isometric and concentric force (3,9,10), enhanced task specific gains in eccentric strength (10), reduced neural inhibition and increase in muscle activation (1,17)....

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  • ...=Consequently this could provide a potentially powerful stimulus for musculoskeletal adaptation and thereby be of use for long-term athlete development to increase muscle strength and size, given that the mechanical stimuli is integral to induce adaptation (10)....

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Journal ArticleDOI
TL;DR: The similar increase in fascicle length observed between the training groups mitigates against contraction mode being the predominant stimulus, and muscle architectural adaptations occur rapidly in response to resistance training but are strongly influenced by factors other than contraction mode.
Abstract: Studies using animal models have been unable to determine the mechanical stimuli that most influence muscle architectural adaptation. We examined the influence of contraction mode on muscle architectural change in humans, while also describing the time course of its adaptation through training and detraining. Twenty-one men and women performed slow-speed (30 degrees /s) concentric-only (Con) or eccentric-only (Ecc) isokinetic knee extensor training for 10 wk before completing a 3-mo detraining period. Fascicle length of the vastus lateralis (VL), measured by ultrasonography, increased similarly in both groups after 5 wk (Delta(Con) = +6.3 +/- 3.0%, Delta(Ecc) = +3.1 +/- 1.6%, mean = +4.7 +/- 1.7%; P < 0.05). No further increase was found at 10 wk, although a small increase (mean approximately 2.5%; not significant) was evident after detraining. Fascicle angle increased in both groups at 5 wk (Delta(Con) = +11.1 +/- 4.0%, Delta(Ecc) = +11.9 +/- 5.4%, mean = 11.5 +/- 3.2%; P < 0.05) and 10 wk (Delta(Con) = +13.3 +/- 3.0%, Delta(Ecc) = +21.4 +/- 6.9%, mean = 17.9 +/- 3.7%; P < 0.01) in VL only and remained above baseline after detraining (mean = 13.2%); smaller changes in vastus medialis did not reach significance. The similar increase in fascicle length observed between the training groups mitigates against contraction mode being the predominant stimulus. Our data are also strongly indicative of 1) a close association between VL fascicle length and shifts in the torque-angle relationship through training and detraining and 2) changes in fascicle angle being driven by space constraints in the hypertrophying muscle. Thus muscle architectural adaptations occur rapidly in response to resistance training but are strongly influenced by factors other than contraction mode.

395 citations


"An Evaluation of Supramaximally Loa..." refers background in this paper

  • ...There is a wealth of evidence to suggest that following habitual use of high intensity eccentric exercise there is an increase in muscle cross-sectional area and morphological alterations of muscle architecture (2), preferential recruitment of type II muscle fibers (13), increase in isometric and concentric force (3,9,10), enhanced task specific gains in eccentric strength (10), reduced neural inhibition and increase in muscle activation (1,17)....

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Frequently Asked Questions (2)
Q1. What are the contributions in this paper?

This study sought to investigate the mechanical characteristics of supramaximally loaded eccentric exercise when using a custom-built leg press machine. This research provides new data regarding the fundamental mechanical characteristics underpinning supramaximally loaded eccentric leg press exercise. The information gathered in the study provides a foundation for practitioners to consider when devising loading strategies, and implementing or evaluating supramaximally loaded eccentric exercise when using a similar exercise and device. 

As such, it seems apt to suggest that future research should establish task-specific methods of eccentric assessment.