Superimposing hip extension on knee flexion evokes higher activation in biceps femoris than knee flexion alone

Hegyi, András; Csala, Dániel; Kovács, Bálint; Péter, Annamária; Liew, Bernard X. W.; Yu, Yue; Finni, Taija; Tihanyi, József; Cronin, Neil J.

doi:10.1016/j.jelekin.2021.102541

Cited by 8 publications

(8 citation statements)

References 49 publications

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“…Third, a variety of methods have been used to analyze the EMG signal (Tables 2 and 3 ). Specifically, length-dependent variations have been assessed using both raw [ 79 , 125 , 143 , 144 , 150 , 152 , 163 ] and normalized [ 127 , 128 , 130 , 132 , 137 , 145 – 147 , 149 , 151 , 154 – 157 , 162 , 164 ] EMG values (Tables 2 and 3 ). Raw EMG values show higher individual variability than normalized EMG values, but they allow direct comparison between different joint angle conditions.…”

Section: Main Textmentioning

confidence: 99%

Hamstrings force-length relationships and their implications for angle-specific joint torques: a narrative review

Kellis

Blazevich

2022

BMC Sports Sci Med Rehabil

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Temporal biomechanical and physiological responses to physical activity vary between individual hamstrings components as well as between exercises, suggesting that hamstring muscles operate differently, and over different lengths, between tasks. Nevertheless, the force-length properties of these muscles have not been thoroughly investigated. The present review examines the factors influencing the hamstrings’ force-length properties and relates them to in vivo function. A search in four databases was performed for studies that examined relations between muscle length and force, torque, activation, or moment arm of hamstring muscles. Evidence was collated in relation to force-length relationships at a sarcomere/fiber level and then moment arm-length, activation-length, and torque-joint angle relations. Five forward simulation models were also used to predict force-length and torque-length relations of hamstring muscles. The results show that, due to architectural differences alone, semitendinosus (ST) produces less peak force and has a flatter active (contractile) fiber force-length relation than both biceps femoris long head (BFlh) and semimembranosus (SM), however BFlh and SM contribute greater forces through much of the hip and knee joint ranges of motion. The hamstrings’ maximum moment arms are greater at the hip than knee, so the muscles tend to act more as force producers at the hip but generate greater joint rotation and angular velocity at the knee for a given muscle shortening length and speed. However, SM moment arm is longer than SM and BFlh, partially alleviating its reduced force capacity but also reducing its otherwise substantial excursion potential. The current evidence, bound by the limitations of electromyography techniques, suggests that joint angle-dependent activation variations have minimal impact on force-length or torque-angle relations. During daily activities such as walking or sitting down, the hamstrings appear to operate on the ascending limbs of their force-length relations while knee flexion exercises performed with hip angles 45–90° promote more optimal force generation. Exercises requiring hip flexion at 45–120° and knee extension 45–0° (e.g. sprint running) may therefore evoke greater muscle forces and, speculatively, provide a more optimum adaptive stimulus. Finally, increases in resistance to stretch during hip flexion beyond 45° result mainly from SM and BFlh muscles.

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Section: Main Textmentioning

confidence: 99%

Hamstrings force-length relationships and their implications for angle-specific joint torques: a narrative review

Kellis

Blazevich

2022

BMC Sports Sci Med Rehabil

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“…Finally, it should be mentioned that in this study biceps femoris and semitendinosus, which are two-joints muscles, were grouped in the hip/back synergy, and not into the knee synergy. This is related to the fact that as for the nature of the task, hamstrings muscles were more deputed to the hip extension than to knee flexion [ 52 , 53 ]. At the same time, quadriceps muscle, which is also a two-joints muscle, was grouped only in the knee synergy.…”

Section: Discussionmentioning

confidence: 99%

Muscle synergies for the control of single-limb stance with and without visual information in young individuals

Labanca

Ghislieri

Knaflitz

et al. 2021

BMC Sports Sci Med Rehabil

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Purpose Single-limb stance is a demanding postural task featuring a high number of daily living and sporting activities. Thus, it is widely used for training and rehabilitation, as well as for balance assessment. Muscle activations around single joints have been previously described, however, it is not known which are the muscle synergies used to control posture and how they change between conditions of normal and lack of visual information. Methods Twenty-two healthy young participants were asked to perform a 30 s single-limb stance task in open-eyes and closed-eyes condition while standing on a force platform with the dominant limb. Muscle synergies were extracted from the electromyographical recordings of 13 muscles of the lower limb, hip, and back. The optimal number of synergies, together with the average recruitment level and balance control strategies were analyzed and compared between the open- and the closed-eyes condition. Results Four major muscle synergies, two ankle-dominant synergies, one knee-dominant synergy, and one hip/back-dominant synergy were found. No differences between open- and closed-eyes conditions were found for the recruitment level, except for the hip/back synergy, which significantly decreased (p = 0.02) in the closed-eyes compared to the open-eyes condition. A significant increase (p = 0.03) of the ankle balance strategy was found in the closed-eyes compared to the open-eyes condition. Conclusion In healthy young individuals, single-limb stance is featured by four major synergies, both in open- and closed-eyes condition. Future studies should investigate muscle synergies in participants with other age groups, as well as pathological conditions.

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“…Thus, bipolar surface EMG recorded from this location is likely to be contaminated by the adjacent muscles (i.e., crosstalk), even if the electrode is centered over the ST, which may not necessarily occur (i.e., slight deviations in the mediolateral position or the muscle retracted past the location). As such, signals recorded via electrodes placed on the posterior thigh to SENIAM guidelines may not accurately reflect ST muscle activity in ACLR legs (where the ST was used as graft donor), which may not necessarily be inferred from synergist muscles because myoelectric activity amplitudes and patterns differ between hamstring muscles (53)(54)(55)(56)(57)(58)(59). Therefore, future work is needed to clarify if signals acquired from a more specific location over the ST may result in different interpretations of ST myoelectric activity post-ACLR compared with data obtained from electrodes placed according to SENIAM guidelines.…”

Section: E Ects Of Muscle Atrophy On Electrode Placement At the Recom...mentioning

confidence: 99%

Semitendinosus muscle morphology in relation to surface electrode placement in anterior cruciate ligament reconstructed and contralateral legs

Kositsky

Barrett

Moulin

et al. 2022

Front. Sports Act. Living

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The semitendinosus tendon is commonly harvested as graft tissue for anterior cruciate ligament reconstruction (ACLR). Although the semitendinosus tendon can regenerate following harvesting, ACLR results in substantial reductions in semitendinosus muscle size and length, potentially complicating electrode placement for electromyography. The purpose of this study was to assess whether the most commonly used electrode placement [recommended by the “Surface Electromyography for Non-Invasive Assessment of Muscles” (SENIAM) project] is appropriate for measuring semitendinosus electromyograms after ACLR. In nine participants (unilateral ACLR with a semitendinosus graft), B-mode ultrasonography was used to bilaterally determine (i) the semitendinosus muscle-tendon junction position and the state of tendon regeneration (latter for the ACLR leg only) and (ii) the anatomical cross-sectional area (ACSA) of the semitendinosus muscle at the SENIAM-recommended electrode placement site at rest and during isometric maximal voluntary contraction (MVC) at two knee joint angles. Depending on the contraction state and joint angle, the semitendinosus muscle had retracted past the recommended placement site in 33–78% of ACLR legs, but not in any contralateral legs. The ACSA of semitendinosus was smaller both at rest and MVC in the ACLR compared to contralateral leg. The ACSA for both legs decreased at MVC compared to rest and at deep compared to shallow knee flexion angles, likely due to sliding of the muscle under the skin. These results suggest SENIAM guidelines are likely unsuitable for recording surface electromyograms from the semitendinosus muscle after tendon harvesting for ACLR as the muscle of interest may not be within the electrode detection volume.

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Superimposing hip extension on knee flexion evokes higher activation in biceps femoris than knee flexion alone

Cited by 8 publications

References 49 publications

Hamstrings force-length relationships and their implications for angle-specific joint torques: a narrative review

Hamstrings force-length relationships and their implications for angle-specific joint torques: a narrative review

Muscle synergies for the control of single-limb stance with and without visual information in young individuals

Semitendinosus muscle morphology in relation to surface electrode placement in anterior cruciate ligament reconstructed and contralateral legs

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