Effect of plyometric training on the fascicle length of the gastrocnemius medialis muscle.
Shintarou Kudo, Takanori Sato, Toshinori Miyashita
PMID 32273650WHAT IT FOUND
Eccentric calf raises increased medial gastrocnemius fascicle length by week 6 in healthy adults; normal calf raises did not.
Dorsiflexion angle and muscle thickness also rose. This is a muscle structure change, not proven performance or injury benefit.
Key findings
01Eccentric calf raises increased medial gastrocnemius fascicle length significantly after six weeks; normal calf raises did not.
02Ankle dorsiflexion angle and muscle thickness increased significantly after three weeks in the eccentric group.
03Pennation angle did not change significantly in either group.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Participants were healthy volunteers with no lower limb injuries, so results may not apply to injured or clinical populations. The sample was small: 21 participants, with 22 legs in the eccentric group and 20 legs in the normal group. Outcomes were ultrasound muscle structure and passive ankle angle, not function, performance, pain, or injury. The paper does not describe blinding, allocation concealment, or dropout handling. The paper reports within-group changes and does not state a between-group statistical comparison. Fascicle length was measured in only one direction, and passive tendon tension was not measured. The fascicle length result text gives baseline and 3-week values while stating significance after six weeks, so the timing of the comparison is unclear.
Declared interests
The authors state they have nothing to declare for this study.
The easy way to misread this
Do not conclude that plyometric or eccentric calf training improves athletic performance or prevents injury. This study measured medial gastrocnemius fascicle length and passive ankle dorsiflexion in healthy volunteers, not performance, function, pain, or injury outcomes.