Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, <i>in vivo</i>

Magnusson, S. Peter; Hansen, Philip; Aagaard, Per; Brønd, Jan Christian; Dyhre‐Poulsen, Poul; Bojsen‐Møller, Jens; Kjær, Michael

doi:10.1046/j.1365-201x.2003.01048.x

Cited by 230 publications

(247 citation statements)

References 31 publications

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“…Arampatzis et al 2007; Kubo et al 2006). Since it is known that the outer tendon and aponeurosis have different mechanical properties (Finni et al 2003;Kubo et al 2005;Magnusson et al 2003), it may be that their adaptability also differs and therefore it can be speculated that adaptation might have occurred at the aponeurosis level, which was not investigated at the present study.…”

Section: Discussionmentioning

confidence: 89%

Neuromuscular mechanics and hopping training in elderly

et al. 2014

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Phone +358-40-8053384 merja.hoffren@jyu.fi 2 ABSTRACT Purpose: The present study examined the effects of repetitive hopping training on muscle activation profiles and fascicletendon interaction in the elderly.Methods: 20 physically active elderly men were randomly assigned for training (TG) and control groups (CG). TG performed supervised bilateral short contact hopping training with progressively increasing training volume. Measurements were performed before the training period (BEF) as well as after 2 weeks (2W) and 11 weeks (11W) of training. During measurements the gastrocnemius medialis -muscle (GaM) fascicle and its outer Achilles tendon length changes during hopping were examined by ultrasonography together with electromyographic (EMG) activities of calf muscles, kinematics, and kinetics.Results: At 2W the ankle joint stiffness was increased by 21.0 ± 19.3 % and contact time decreased by 9.4 ± 7.8 % in TG.Thereafter, from 2-11W the jumping height increased 56.2 ± 18.1 % in TG. Simultaneously tendon forces increased 24.3 ± 19.0 % but tendon stiffness did not change. GaM fascicles shifted to shorter operating lengths after training without any changes in their length modifications during the contact phase of hopping. Normalized EMG amplitudes during hopping did not change with training.Conclusions: The present study shows that 11 weeks of hopping training improves the performance of physically active elderly men. This improvement is achieved with shorter GaM operating lengths and therefore increased fascicle stiffness and improved tendon utilization after training. Based on these results hopping training could be recommended for healthy fit elderly to retain and improve rapid force production capacity.

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Section: Discussionmentioning

confidence: 89%

Neuromuscular mechanics and hopping training in elderly

et al. 2014

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“…The subjects lied supine with relative internal hip, knee and ankle angles of 180º, 180º and 90º respectively. In this joint modulation the gastrocnemius muscles were at mechanically advantageous length for maximal force production (24). The axis of their right ankle was aligned with the axis of rotation of the dynamometer.…”

Section: Ankle Joint Torque Testingmentioning

confidence: 99%

“…The passive mode data were used to correct the elongation of MTJ caused by ankle rotation during the main isometric testing (24). Consequently, before isometric tests, a passive motion test at 5°/s in a range of motion (80°and 135°) was performed.…”

Section: Joint Correctionmentioning

confidence: 99%

“…Consequently, before isometric tests, a passive motion test at 5°/s in a range of motion (80°and 135°) was performed. The displacement of each ultrasound (US) image point marker during the passive joint movement was used to correct MTJ elongation values caused by ankle rotation during the main isometric testing (24). Subsequently, the video images obtained during ramp contraction were used to digitize (in each frame) the following points: the MTJ and tendon.…”

Section: Joint Correctionmentioning

confidence: 99%

“…The elongation was measured as the displacement of the distal myotendinous junction of the MG in the transition from a resting state to MVC (24). Peak tendon strain was defined as the relative elongation of the tendon associated with peak tendon force relative to its resting length (Figure 1).…”

Section: Calculation Of Tendon Strainmentioning

confidence: 99%

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Effects of Two Plyometric Protocols at Different Surfaces on Mechanical Properties of Achilles Tendon in Children

et al. 2018

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Objectives: The purpose of this study was to compare the changes in muscle strength and Achilles tendon strain after two plyometric training programs performed on different surfaces in children. Methods:Thirty six children (21 girls, 15 boys) aged 9.30 ± 0.55 years were assigned into a mini-trampoline plyometric group (TPLG), a ground-plyometric group (GPLG) and a control group (CG). The training groups completed a 4-week plyometric intervention (PL) (three-times a week), consisting of hopping exercises performed either on a mini-trampoline (TPLG) or ground (GPLG). Achilles tendon strain, peak ankle plantar flexion torque (PAT), and rate of torque development (RTD) at 3 different angular positions of the ankle (15°, 0°and -15°) were measured before and after training. Results:The main finding of this study was that Achilles tendon strain decreased significantly after plyometric training performed on a mini-trampoline or ground surface ( 25% and 15%, for the TPLG and GPLG, respectively (P < 0.05)). This was accompanied by an increase in maximum ankle MVC torque and an increase in RTD (at 15°, 0°positions) for both experimental groups. Especially, statistically significant increases in PAT (30%) and RTD (14%) (P < 0.05) were found for the TPLG while for the GPLG group the increase was 19 % and 8% for PAT and RTD, respectively (P < 0.05). Conclusions: Both protocols show similar adaptations regardless of the surface of training. Training on elastic surface should be incorporated into exercise programs aiming either to enhance strength performance safely, or to achieve the target goal which is not only the safe performance but also the muscle-tendon system efficiency.

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How Alive are Tendons? Metabolic and Circulatory Activity Associated with Exercise in Humans

Kjær¹,

Langberg²,

Boushel³

et al. 2007

Tendinopathy in Athletes

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Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, in vivo

Abstract: The free Achilles tendon demonstrates greater strain compared with that of the distal (deep) aponeurosis during voluntary isometric contraction, which suggests that separate functional roles may exist during in vivo force transmission.

Cited by 230 publications

References 31 publications

Neuromuscular mechanics and hopping training in elderly

Neuromuscular mechanics and hopping training in elderly

Effects of Two Plyometric Protocols at Different Surfaces on Mechanical Properties of Achilles Tendon in Children

How Alive are Tendons? Metabolic and Circulatory Activity Associated with Exercise in Humans

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