Study note • PMID 38809851
The effect of forward postural lean on running economy, kinematics, and muscle activation.
How to use this page
This note summarizes one study record. Check the participants, methods, results, and limitations before applying it to training.
- • Controlled within-runner conditions support the direction of the acute metabolic effect.
- • The small sample and laboratory manipulation limit generalization and long-term prescription.
- • The low-risk practical action is to avoid forcing an exaggerated lean, not to prescribe one perfect posture.
ELI5
In plain language
In 16 healthy young runners, deliberately increasing forward lean to about 8 degrees made running less economical, not more.
Metabolic cost increased by 8% whether runners leaned from the ankle or the waist, alongside greater hip flexion and more glute and hamstring activation.
The practical message is not to force an exaggerated lean. A natural upright or moderate posture may cost less energy for runners similar to this study.
Takeaways
What the abstract suggests
- • A large, deliberately imposed forward lean worsened running economy by increasing metabolic cost 8%.
- • The result was similar whether the lean came from the ankle or the waist.
- • Large lean also increased hip flexion and extensor-muscle demand during stance.
- • Do not interpret 'lean forward' as a cue to force posture; this study supports a natural upright-to-moderate range instead.
Protocol
Protocol (as reported)
- • Sixteen healthy runners (8 women and 8 men; mean age 23 years) ran on a motorized treadmill.
- • Running speed was fixed at 3.58 m/s across the conditions.
- • Posture conditions were upright, moderate lean at 50% of each runner's maximal lean, and maximal lean up to about 8 degrees.
- • Runners used both ankle-lean and waist-lean strategies while researchers measured metabolic cost, kinematics, and muscle activation.
Fit
Who it may help, and who should be cautious
Who it helps
- • Runners and coaches deciding whether an exaggerated forward-lean cue is likely to improve economy.
- • Healthy adult runners comparing posture cues at a steady submaximal speed.
- • Athletes who can test form changes conservatively without disrupting their natural gait.
Who should be cautious
- • Do not use this study as a reason to force a rigid upright posture or self-correct pain-related gait changes.
- • Runners with injury, neurological symptoms, or clinically significant gait concerns should seek qualified assessment.
- • Do not generalize an acute treadmill manipulation into a long-term gait-retraining prescription.
Methods
What the study actually did
- • Controlled acute treadmill study published in PLOS ONE in 2024.
- • Compared three lean angles and two lean strategies within the same 16 runners.
- • Measured metabolic energy consumption, lower-limb kinematics, and muscle activation.
- • Tested the coaching belief that more forward lean improves running economy.
Full paper
What the full paper adds
- • Participants were 16 healthy runners, evenly split between women and men, with a mean age of 23 years.
- • They ran at 3.58 m/s using upright, moderate, and maximal forward-lean conditions.
- • The large-lean condition increased metabolic cost by 8% and increased hip flexion, gluteus maximus activation, and biceps femoris activation.
- • The running-economy response did not differ meaningfully between leaning from the ankle and leaning from the waist.
Results excerpt
What the abstract reports
“Large forward lean raised metabolic cost 8% and increased hip flexion and extensor-muscle activation.”
Note: excerpts are short; for full context, read the paper.
Limits
Limitations and bias
- • The sample contained only 16 healthy young adults, so estimates are imprecise and may not generalize broadly.
- • The study tested an acute posture change at one treadmill speed rather than long-term adaptation outdoors.
- • Maximal imposed lean is not the same as a runner's natural posture during racing or fatigue.
- • The study measured economy and biomechanics, not race performance, injury risk, or coaching outcomes.
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