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Differences in joint power distribution in high and low lactate threshold cyclists.
Brian K Leary1, Heath M Burton1, Emre Vardarli1
1Human Performance Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, One University Station, Austin, TX, 78712, USA.
European Journal of Applied Physiology
|October 7, 2020
Summary
High lactate threshold (HLT) cyclists utilize their hip joint more for power during intense cycling. This biomechanical strategy may reduce knee extensor muscle stress and lactate production.
Area of Science:
- Sports Biomechanics
- Exercise Physiology
Background:
- Understanding biomechanical differences in cyclists with varying blood lactate thresholds (LT) is crucial for optimizing performance.
- High LT cyclists (80% VO2max) may employ different movement strategies compared to low LT cyclists (70% VO2max).
Purpose of the Study:
- To investigate the biomechanical distinctions between high blood lactate threshold (HLT) and low blood lactate threshold (LLT) cyclists.
- To test the hypothesis that HLT cyclists minimize knee extensor muscle stress by increasing hip joint contribution during high-intensity cycling.
Main Methods:
- Sixteen trained cyclists were divided into HLT (n=8) and LLT (n=8) groups based on their LT during cycling.
- Joint-specific powers (knee and hip) were calculated using inverse dynamics during cycling at 60-90% VO2max.
Main Results:
- No significant differences in running LT were observed between groups.
- LLT cyclists showed increased knee joint power with work rate, while HLT cyclists did not.
- HLT cyclists demonstrated significantly greater relative hip power contribution at 90% VO2max compared to LLT cyclists.
Conclusions:
- HLT cyclists exhibit a greater relative hip power contribution during high-intensity cycling (90% VO2max).
- This suggests that distributing work between hip and knee joints may be a strategy employed by HLT cyclists to reduce muscle stress and potentially delay lactate accumulation.
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