Efficacy of Static Stretching and Proprioceptive Neuromuscular Facilitation Stretch on Hamstrings Length After a Single Session

Abstract

A number of studies have investigated the efficacy of several repetitions of proprioceptive neuromuscular facilitation stretching (PNF) and static stretching (SS). However, there is limited research comparing the effects of a single bout of these stretching maneuvers. The aim of this study was to compare the effectiveness of a single bout of a therapist-applied 30-second SS vs. a single bout of therapist-applied 6-second hamstring (agonist) contract PNF. Forty-five healthy subjects between the ages of 21 and 35 were randomly allocated to 1 of the 2 stretching groups or a control group, in which no stretching was received. The flexibility of the hamstring was determined by a range of passive knee extension, measured using a universal goniometer, with the subject in the supine position and the hip at 90° flexion, before and after intervention. A significant increase in knee extension was found for both intervention groups after a single stretch (SS group = 7.53°, p < 0.01 and PNF group = 11.80°, p < 0.01). Both interventions resulted in a significantly greater increase in knee extension when compared to the control group (p < 0.01). The PNF group demonstrated significantly greater gains in knee extension compared to the SS group (mean difference 4.27°, p < 0.01). It can be concluded that a therapist applied SS or PNF results in a significant increase in hamstring flexibility. A hamstring (agonist) contract PNF is more effective than an SS in a single stretching session. These findings are important to physiotherapists or trainers working in clinical and sporting environments. Where in the past therapists may have spent time conducting multiple repetitions of a PNF and an SS, a single bout of either technique may be considered just as effective. A key component of the study methodology was the exclusion of a warm-up period before stretching. Therefore, the findings of efficacy of a single PNF are of particular relevance in sporting environments and busy clinical settings where time may be limited.

Comparação do alongamento estático, balístico e contrair-relaxar nos músculos isquiotibiais

“…The results of PT suggest that the ballistic and contract-relax stretching were able to increase the immediate flexibility of the hamstring muscles. These data corroborate the findings of other studies on the implementation of stretching protocols to increase the flexibility of the hamstring muscles 15,16 . There are several techniques to assess changes in muscle flexibility based on the joint and movements to be evaluated.…”

“…This property is a response of the muscle-tendon unit to stretching with fixed length, which generates a decrease in stress over time. This reduced length of the muscle-tendon unit is known as stress relaxation and allows a deformed of the muscle-tendon unit more easily in the next repetition, thus providing greater flexibility 16 . Another explanation found is based on the increased tolerance of the muscletendon unit to elongation, although this mechanism is still unknown 21 .…”

Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review

“…A number of studies report greater ROM improvements after PNF compared with SS within a single session (Etnyre and Lee 1988;Ferber et al 2002;O'Hora et al 2011). On the other hand, SS has also been shown to provide ROM increases similar to those of PNF within a single session (Condon and Hutton 1987;Maddigan et al 2012).…”

Efeito agudo de diferentes rotinas de alongamento estático sobre o salto com contramovimento.

“…A ausência de melhora na ADM para a condição AL-10 foi inesperada, uma vez que evidências na literatura apontam para efeito agudo sobre a ADM com volumes curtos de alongamento estático (O'HORA et al, 2011). De certa forma, pode-se sugerir que a ausência de aumento agudo na ADM após o AL-10s esteja diretamente ligada ao aumento significativo na altura do salto uma vez que a queda na rigidez passiva da unidade músculo-tendínea é uma das responsáveis pelo aumento da ADM e também pela queda no desempenho da força (MIZUNO; MATSUMOTO; UMEMURA, 2014).…”