ReviewFrontiers in physiology2021
Establishing Reference Values for Isometric Knee Extension and Flexion Strength.
Review in Frontiers in physiology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 30 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
30 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Pooled it
- First-in-human study of epidural spinal cord stimulation in individuals with spinal muscular atrophy.Nature medicine · 2025Trial
- Altered Skeletal Muscle Phosphate Metabolism After Muscle Damage Is Associated With Elevated Effort Perception During Exercise in Humans.Scandinavian journal of medicine & science in sports · 2026Article
- Sex Differences in Knee Flexor Strength and Limb Symmetry Across Different Strength Testing Conditions in Healthy Recreational Athletes.Journal of clinical medicine · 2026Article
- Modifying the Meaning of the Upper Anchor Predictably Shapes Ratings of Perceived Effort: A Randomized Crossover Trial.Sports medicine - open · 2026Article
- Intra- and inter-session reliability of the MyotonPro in measuring the biomechanical and viscoelastic properties of the knee extensor and flexor muscles.BMC sports science, medicine & rehabilitation · 2026Article
- Sex Differences in Intraocular Pressure and Retinal Vessel Responses After Sustained Isometric Knee Extension in Young Adults: A Quasi-Experimental Study.Journal of clinical medicine · 2026Article
- Clinical and functional outcomes of fracture pattern-driven plate osteosynthesis technique for comminuted patellar fractures using multiple miniplates.Archives of orthopaedic and trauma surgery · 2026Article
- Computational biomechanics of human knee joint in maximum voluntary isometric extension with focus on the role of joint center positioning.Scientific reports · 2026Article
- Neuromuscular adaptations to load-matched isometric vs. dynamic resistance training in Kho-Kho athletes: a pilot investigation.Frontiers in sports and active living · 2026Article
- Spatiotemporal gait parameters and ground reaction force analysis in female non-gymnastsFrontiers in bioengineering and biotechnology · 2026Article
- Normalized data may have limitations in determining the reliability of MVC measurements.Scientific reports · 2025Article
- Association of Knee Pain Frequency and Severity with Quadriceps Strength but Not Rate of Decline Over Four Years.ACR open rheumatology · 2025Article
- Fatigue-induced changes in electromyographic activity after repeated racing turns: a pilot study.European journal of applied physiology · 2025Article
- Factors associated with impaired physical functionality in X-linked hypophosphatemia.JBMR plus · 2025Article
- Normative isokinetic knee strength values and prediction models in non-athletic Chinese adults.Frontiers in bioengineering and biotechnology · 2025Article
- Adults born preterm have lower peripheral skeletal muscle area and strength.Scientific reports · 2024Observational
- Article
- Resistance Exercise Program Is Feasible and Effective in Improving Functional Strength in Post-COVID Survivors.Journal of clinical medicine · 2024Article
- Absolute and Normalized Normative Torque Values of Knee Extensors and Flexors in Healthy Trained Subjects: Asymmetry Questions the Classical Use of Uninjured Limb as Reference.Arthroscopy, sports medicine, and rehabilitation · 2024Article
Corrections and comments
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Authors and funding
3 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Single-joint isometric and isokinetic knee strength assessment plays an important role in strength and conditioning, physical therapy, and rehabilitation. The literature, however, lacks absolute reference values. We systematically reviewed the available studies that assessed isometric knee strength. Two scientific databases (PubMed and PEDro) were searched for the papers that are published from the inception of the field to the end of 2019. We included studies that involved participants of both genders and different age groups, regardless of the study design, that involved isometric knee extension and/or flexion measurement. The extracted data were converted to body-mass-normalized values. Moreover, the data were grouped according to the knee angle condition (extended, mid-range, and flexed). A meta-analysis was performed on 13,893 participants from 411 studies. In adult healthy males, the pooled 95% confidence intervals (CI) for knee extension were 1.34-2.23Nm/kg for extended knee angle, 2.92-3.45Nm/kg for mid-range knee angle, and 2.50-3.06Nm/kg for flexed knee angle, while the CIs for flexion were 0.85-1.20, 1.15-1.62, and 0.96-1.54Nm/kg, respectively. Adult females consistently showed lower strength than adult male subgroups (e.g., the CIs for knee extension were 1.01-1.50, 2.08-2.74, and 2.04-2.71Nm/kg for extended, mid-range, and flexed knee angle condition). Older adults consistently showed lower values than adults (e.g., pooled CIs for mid-range knee angle were 1.74-2.16Nm/kg (male) and 1.40-1.64Nm/kg (female) for extension, and 0.69-0.89Nm/kg (male) and 0.46-0.81Nm/kg (female) for flexion). Reliable normative for athletes could not be calculated due to limited number of studies for individual sports.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.