ORIGINAL RESEARCH article
Front. Physiol.
Sec. Exercise Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1654030
This article is part of the Research TopicNeurophysiological Basis of the Relationship between Core Stability and Human Movement: Implications for Sport and RehabilitationView all 8 articles
Maximal isometric and eccentric hamstring strength are influenced by body mass and additional load: Does the critical point at which maximum eccentric strength is achieved play a role?
Provisionally accepted- 1Departement of Elementary Education, Riau University, Pekanbaru, Indonesia
- 2Univerzita Komenskeho v Bratislave, Bratislava, Slovakia
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Isometric (ISO) and eccentric (ECC) hamstring tests are used to assess peak force at various knee angles. However, it is unknown to what extent body weight influences the so-called “critical point” at which individuals achieve their maximal knee flexor force production. This study compared (1) peak force isometric contraction at 60o knee flexion without body weight, with body weight and added weight, (2) eccentric knee flexor strength during Nordic hamstring exercise (NHE) up to 60o of knee flexion with body weight and added weight, as well as up to an angle of 20o with body weight. The relationship between peak isometric strength in all loading conditions and eccentric strength during NHE performed to different knee angles was also investigated. 22 male athletes (age 21.7±4.3 years, height 181.6±7.5 cm, body mass 75.4±8.5 kg) completed i) maximal efforts on isometric knee flexion at 60º (ISO60), with body weight (ISO60-BW), and with 5 kg medicine ball (ISO60-BW+AW), ii) NHE with lean forward from 90o to 60º with body weight (ECC60-BW) and a 5 kg medicine ball (ECC60-BW+AW), and iii) NHE with lean forward up to 20o with body weight (ECC20). Results showed higher peak force during ISO60-BW+AW compared to ISO60-BW (24.2 N, 6.5%, p=0.012), and ISO60 (42.1 N, 11.6%, p=0.000). The added 5 kg (ECC60-BW+AW) produced greater eccentric force compared to body weight (ECC60-BW) (17.9 N, 6.4%; p=0.03). However, there was no significant difference between NHE with body weight and added weight, irrespective of subject's ability to achieve a final position of 20o of knee flexion. Relative eccentric force was higher in participants who achieved 20º than in those who reached their critical point at 45º of knee flexion (p=0.001, d=1.89). Peak isometric force in all three conditions significantly correlated with NHE peak force at 45º (r=0.79-0.90) and 20º of knee flexion (r=0.71-0.77), explaining 62-81% and 49-58% of the variance, respectively. These findings indicate that isometric and eccentric measures of hamstring strength are interdependent. However, eccentric hamstring strength during NHE is more dependent on maximal hamstring strength when this exercise is performed to a critical point of 45º than 20º of knee flexion.
Keywords: eccentric contraction, Knee flexor strength, Nordic Hamstring exercise, Peak force, Isometric Contraction
Received: 25 Jun 2025; Accepted: 21 Aug 2025.
Copyright: © 2025 Sinulingga and Zemková. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Andrew Rinaldi Sinulingga, Departement of Elementary Education, Riau University, Pekanbaru, Indonesia
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