Behavior of creatine kinase in a variable resistance session.
Álvaro Huerta Ojeda, Sergio Galdames Maliqueo, Guillermo Barahona-Fuentes and 1 others
PMID 31417212WHAT IT FOUND
Creatine kinase rose after both the variable-resistance and no-variable-resistance sessions in six female sprinters.
Back-squat variable-resistance pre-activation also improved 30-m sprint times, so the gain was not free of a muscle-damage marker increase.
Key findings
01Six female sprinters had higher creatine kinase markers 24 hours after both the variable-resistance and control sessions.
02Only the variable-resistance condition improved 30-m sprint times (p<0.05).
03Back squat velocity did not change after the variable-resistance condition (p>0.05).
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only six female sprinters were studied, so the findings cannot be generalised to male athletes, less trained athletes, or patients. The paper does not describe randomisation or blinding of the sessions. The stated primary outcome was creatine kinase behaviour, but the positive result was a sprint-time outcome. Creatine kinase and lactate increased after both conditions, so the study did not show that variable resistance reduced muscle-damage markers. The suggestion to use rest periods longer than 24 hours was not tested in the study.
Declared interests
The authors declared no conflicts of interest.
The easy way to misread this
Do not read the improved 30-m sprint times as proof that back-squat variable-resistance pre-activation is a better or less muscle-damaging option. Only six female sprinters were studied, and creatine kinase rose after both the variable-resistance and no-variable-resistance sessions.