PERFORMANCE BASED MEASURES OF RECOVERY IN POWERSPEED SPORTS

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PERFORMANCE BASED MEASURES OF RECOVERY IN
POWER/SPEED SPORTS
Brad McGregor Kevin Serre
2
OVERVIEW

• Definitions
• Where are we at?
• Central measures of fatigue
• Peripheral measures of fatigue
• Summation
• Research suggestions
• References

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DEFINITIONS

• Central fatigue insufficient neural drive to
  the muscles (Garrandes et al. 2005)
• Peripheral fatigue changes beyond the
  neuromuscular junction (Garrandes et al. 2005)
• Neural plasticity - the process whereby patterns
  of impulses into mature synapses can cause
  long-lasting changes in the magnitude of the
  subsequent stimulation (Armstrong VanHeest,
  2002)

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WHERE ARE WE AT?

• Most research has concentrated on metabolic
  biochemical markers
• Neural processes are not well understood,
  particularly how they respond to exercise
• Techniques to measure NCV, neural drive reflex
  response need consistency refinement
• Most research admits difficulty in
  differentiating between central peripheral
  fatigue
• Markers showing promise include power decrement,
  EMGforce ratio, reflex inhibition, NCV

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CENTRAL MEASURES

• Noakes (2000)
• Brain neurotransmitter alters rate coding
  during exercise
• CNS deactivates as a protective mechanism (some
  support for this theory)
• Hautier et al. (2000) constant EMGforce ratio
  concurrent with force decrease
• Ross et al. (2001) NCV is promising
• Koceja et al. (2004) Hmaxmmax ratio
• Reflex sensitivity most support in literature
  but can be affected by metabolic by-products
• CMJ research inconclusive but promising

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PERIPHERAL MEASURES

• High frequency model impaired AP propagation
  along muscle fibre
• Paasuke et al. (1999) electromechanical delay
• Glaister et al. (2005) - metabolic acidosis is
  not a limiting factor in excitation-contraction
  coupling (no EMG)
• Jereb and Strojnik (2003) imbalance of Na
  K impair AP propagation

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SINGLE-LEG HOP STUDY
Augustsson et al. 2006
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SUMMARY

• Trial error with a combination of markers (ie
  PT reflex inhibition power decrement)
• Power decrement assessment is simple results
  are immediate (event implications)
• The central vs peripheral debate appears
  academic (what are the practical implications?)
• Consider neural plasticity vs fatigue for
  different sports individuals

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RESEARCH SUGGESTIONS

• Correlations between biochemical neural
  markers
• More studies using trained subjects dynamic
  fatigue protocols
• Efficacy of simple reaction-time tests in the
  field
• Validity of field measures (single-leg hop)
  compared to lab tests

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REFERENCES

• 1. Armstrong, L.E. and VanHeest, J.L. The unknown
  mechanism of the overtraining syndrome. Clues
  from depression and psychoneuroimmunology. Sports
  Med. 32(3)185-209, 2002.
• 2. Garrandes, F., Colson, S.S., Pensini, M. and
  Legros, P. Neuromuscular fatigue kinetics are
  sport specific. Computer Methods in Biomechanics
  and Biomedical Engineering. Supplement 1113-114,
  2005.
• 3. Augustsson, J., Thomee, R., Linden, C.,
  Folkesson, M., Tranberg, R. and Karlsson, J.
  Single-leg hop testing following fatiguing
  exercise reliability and biomechanical analysis.
  Scandinavian Journal of Medicine and Science in
  Sports. 16111-120, 2006.
• 4. Hautier, C.A., Arsac, L.M., Deghdegh, K.,
  Souquet, J., Belli, A. and Lacour, J. Influence
  of fatigue on EMG/force ratio and cocontraction
  in cycling. Medicine and Science in Sports and
  Exercise. 32(4)839-843, 2000.
• 5. Koceja, D.M., Davison, E. and Robertson, C.T.
  Neuromuscular characteristics of endurance-and
  power-trained athletes. Research Quarterly for
  Exercise and Sport.75(1)23-30, 2004.
• 6. Noakes, T.D. Physiological models to
  understand exercise fatigue and the adaptations
  that predict or enhance athletic performance.
  Scandinavian Journal of Medicine and Science in
  Sports. 10123-145, 2000.
• 7. Paasuke, M., Ereline, J. and Gapeyeva, H.
  Neuromuscular fatigue during repeated exhaustive
  submaximal static contractions of knee extensor
  muscles in endurance-trained, power-trained and
  untrained men. Acta Physiol Scand. 166319-326,
  1999.
• 8. Ross, A., Leveritt, M. and Riek, S. Neural
  influences on sprint running. Training
  adaptations and acute responses. Sports Med.
  31(6)409-425, 2001.
• 9. Jereb, B. and Strojnik, V. Neuromuscular
  fatigue after short maximal cycling exercise.
  Kinesiology. 35(2)135-142, 2003.
• 10. Glaister, M., Stone, M., Stewart, A.M.,
  Hughes, M. and Moir, G.L. The influence of
  recovery duration on multiples sprint cycling
  performance. Journal of Strength and Conditioning
  Research. 19(4)831-837, 2005.