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Effect of PNF stretching training on the properties of human muscle and tendon structures
Author(s) -
Konrad A.,
Gad M.,
Tilp M.
Publication year - 2015
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12228
Subject(s) - tendon , chemistry , muscle contraction , biophysics , medicine , physical medicine and rehabilitation , anatomy , biology
The purpose of this study was to investigate the influence of a 6‐week proprioceptive neuromuscular facilitation ( PNF ) stretching training program on the various parameters of the human gastrocnemius medialis muscle and the Achilles tendon. Therefore, 49 volunteers were randomly assigned into PNF stretching and control groups. Before and after the stretching intervention, we determined the maximum dorsiflexion range of motion ( RoM) with the corresponding fascicle length and pennation angle. Passive resistive torque ( PRT ) and maximum voluntary contraction ( MVC ) of the musculo‐articular complex were measured with a dynamometer. Muscle‐tendon junction ( MTJ ) displacement allowed us to determine the length changes in tendon and muscle, and hence to calculate stiffness. Mean RoM increased from 31.1 ± 7.2° to 33.1 ± 7.2° ( P = 0.02), stiffness of the tendon decreased significantly in both active (from 21.1 ± 8.0 to 18.1 ± 5.5 N/mm) and passive (from 12.1 ± 4.9 to 9.6 ± 3.2 N/mm) conditions, and the pennation angle increased from 18.5 ± 1.8° to 19.5 ± 2.1° ( P = 0.01) at the neutral ankle position (90°), only in the intervention group, whereas MVC and PRT values remained unchanged. We conclude that a 6‐week PNF stretching training program increases RoM and decreases tendon stiffness, despite no change in PRT .