Kinematic alterations after two high-intensity intermittent training protocols in endurance runners
Question
Do 10 x 400 m and 40 x 100 m high-intensity intermittent running protocols alter running kinematics in trained endurance runners?
Summary
Eighteen trained runners completed two demanding interval-running sessions one week apart. Despite high lactate, RPE, and heart-rate responses, the study did not find significant within-session deterioration in the measured running kinematics from the first to the last repetition.
Methodology
- Recreationally trained endurance runners.
- 18 participants.
- Track running.
- Work intervals: 400 m run.
- Recovery: 90-120 s passive standing recovery.
- Intensity: Above vVO2max; self-selected hard pace.
- single session.
- single session.
- Acute counterbalanced crossover biomechanics study
- Running kinematics, Foot strike pattern, and Physiological strain were tracked.
Outcomes
Kinematics
No significant first-to-last repetition kinematic changes occurred within either protocol.
p>=0.05.
Protocol differences
The 40 x 100 m protocol was faster and showed different contact, step, hip, knee, and ankle measures.
Reported p values ranged from p<0.001 to p=0.031.
Foot strike
Foot strike pattern did not significantly change within or between protocols.
Between protocols p=0.135; 10 x 400 m p=0.392; 40 x 100 m p=0.317.
Insights
- In trained runners, acute interval sessions above vVO2max did not cause clear deterioration in measured sagittal-plane kinematics.
- Short 100 m repeats produced faster running and different mechanics than 400 m repeats, even with matched total distance.
- The result should not be used as safety evidence for beginners.
Limitations
- Small athlete sample with only two women.
- Acute study without injury follow-up.
- Sagittal-plane two-dimensional video was used.
- Only the right leg was analyzed.
Safety
- No adverse events or injuries during the study were reported.
- Participants had no injury history in the previous 3 months and were medically examined annually.
- The authors noted that no general clinical examination was performed by the study.