Closed chain assessment of quadriceps activation using the superimposed burst technique

Grant E. Norte, Christopher Kuenze, Joseph M. Hart

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The superimposed burst technique is used to estimate quadriceps central activation ratio during a maximal voluntary isometric contraction, which is calculated from force data during an open-chain knee extension task. Assessing quadriceps activation in a closed-chain position would more closely simulate the action of the quadriceps during activity. Our aim was to determine the test-retest reliability of the quadriceps central activation ratio in the closed chain. Methods: Twenty-two healthy, active volunteers (13M/12F; age. = 23.8. ±. 3; height. = 72.7. ±. 14.5. cm; mass. = 175.3. ±. 9.6. kg) were recruited to participate. Knee extension MVIC torque and the peak torque during a superimposed electrical stimulus delivered to the quadriceps during an MVIC were measured to estimate quadriceps CAR. Interclass correlation coefficients were used to assess test-retest reliability between sessions, and Bland-Altman plots to graphically assess agreement between sessions. Results: Test-retest reliability was fair for CAR (ICC2,k=0.68; P=0.005), with a mean difference of -2.8±10.3%, and limits of agreement ranging -23.1-18.1%. Conclusions: CAR calculated using the superimposed burst technique is moderately reliable in a closed-chain position using technique-based instruction. Although acceptable reliability was demonstrated, wide limits of agreement suggest high variability between sessions.

Original languageEnglish (US)
Pages (from-to)341-347
Number of pages7
JournalJournal of Electromyography and Kinesiology
Issue number3
StatePublished - Jun 2014


  • Central activation ratio
  • Electrical stimulation
  • Test-retest reliability

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Biophysics
  • Clinical Neurology


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