The Effect of One or Three Repetitions of Target-Muscle PNF on Acute Hamstring Extensibility Bonarrigo T, Cristovão S, Lau R, Kaljusto K, Read A. Amsterdam University of Applied Sciences

Introduction

Methods

Results

Discussion & Conclusions

Hamstrings injury is a common sport injury, and stretching has been recommended to prevent this type of injury (Franklin et al. 2000, Thacker et al. 2004, Orchard et al. 2005). Therefore it is important to consider how to best optimise flexibility of the hamstring muscles in healthy individuals.

Variables Independent variable: Number of repetitions of TM-PNF stretching intervention (one versus three repetitions of TM-PNF). Dependent variable: Hamstring extensibility as measured by the SRT in centimetres (cm) to the closest 0.5 cm.

The research question: no significant differences were found between the two intervention groups at baseline. A within-group analysis showed significant difference in SRT pre- vs. postintervention for both groups.

Clinical Relevance: PNF Protocol development

If we can better understand how to attain optimal the benefits of TM-PNF stretching of the hamstrings, we can recommend to therapists a treatment tool to use that is time efficient, and may therefore be incorporated easily into a rehabilitation session as well as part of home exercise program.

Outcome Measures Primary Outcome Measure: Different in score of Sit and Reach Test (SRT) in centimetres (cm) to the closest 0.5 cm between pre- and post-intervention. Secondary Outcome Measure: Gender, BMI, practicing yoga.

Purpose

Equipment Measurement: Sit and Reach Box Analysis: SPSS® 22.0 statistical package

To determine if three repetitions of TM-PNF are more effective than a single repetition of TM-PNF for improving acute extensibility of the hamstring muscles.

Participants Population: ESP students. Inclusion Criteria: 1. Between 18 to 40 years of age, regardless of gender and nationality. 2. Able to understand written and spoken English. Exclusion Criteria: 1. Injury to the lumbar spine or lower extremity in the past three months, structural damage to the hamstrings (joints, muscles, skin). 2. Having participated in an exercise activity 12 hours prior to the trial. 3. Inability to reach / reaching the maximum on the Sit and Reach box for the baseline measurement. 4. Informed consent not obtained.

SRT measurements Intervention group 0

Merits of the clinical study: -  SRT validity -  Blinding -  2 separate PTs for 2 interventions Primary Limitation: -  Absence of control group Secondary Limitation: -  Verifying that participants accurately followed instructions

Recommendations SRT measurements Intervention group 1

-  Control group -  Hamstring injury -  Outside age range

References

Procedures Randomisation was employed with identity codes and the Microsoft Excel randomising function. Concealed allocation was achieved by randomising participants’ identity codes to interventions, and upon allocation of an identity code, would the corresponding intervention be revealed.

However no significant differences in SRTpost could be found as a result of the the betweengroup analysis. A small effect size (0,13) was calculated with the Cohen’s d coefficient SRTpost Intervention group 0 and 1

•  O’Hora J, Cartwright A, Wade C, Hough A, Shum G. Efficacy of static stretching and proprioceptive neuromuscular facilitation stretch on hamstrings length after a single session. J Strength Cond Res. 2011;25(6):1586-1591. •  Spernoga S, Uhl T, Arnold B, Gansneder B. Duration of maintained hamstring flexibility after a one-time, modified hold-relax stretching protocol. J Ath Train. 2001;36(1):44-48. •  Thacker S, Gilchrist J, Stroup D, Kimsey C. The impact of stretching on sports injury risk: A systematic review of the literature. Med Sci Sports Exerc. 2004;36(3):371–378.

Triple-blinding was achieved (participants, data collectors, assessors). A standardised operating procedure was utilised.

Acknowledgements

Data analysis was run by means of IBM® SPSS® version 22.0 on selected continuous and categorical variables.

Contact details

The authors thank Mr. Jesse Arden for his assistance in the planning of this study and research article.

Karit Kaljusto [email protected]