The Effects of PNF Stretching on Hamstring Flexibility

The Effects of PNF Stretching on Hamstring Flexibility in Female Collegiate Soccer and Volleyball Players By: Kristina Everding, Emily Lensing, Shannon Ditsch, and Danielle Vujovic

Introduction �Hamstring flexibility in female soccer and volleyball players �Benefits in PNF stretching �Volleyball players more flexible

Introduction Cont. �Three large muscle groups:

Introduction Cont. �Tested three types of PNF stretching: Hold and Relax Contract and Relax with opposing muscle contraction �PNF relies on neuromuscular characteristics in order to relax the muscles �Improve flexibility by inhibiting muscle contraction

Introduction Cont. �Studies are very contradictory �More research needed

Participants � 24 total NCAA Division III female athletes � 12 soccer players � 12 volleyball players �All were between the ages of 18 -23 �No current hamstring injuries �Participants for each team had similar fitness levels

Measures, Instruments, Tasks �V Sit and Reach Box Used to measure flexibility of lower back and hamstrings

Measures, Instruments, Tasks �V Sit and Reach Test Protocol Sitting on the ground Legs straight out in front with knees flat to the ground with no shoes on Feet are pressed against the V Sit and Reach Box Participant will reach with both hand push the knob as far as they can They did they 3 times and took their best score

Measures, Instruments, Tasks �Proprioceptive Neuromuscular Facilitation (PNF) Hold-Relax Contract-Relax with opposing muscle contraction

Procedure � 6 different trial days (nonconsecutive) �On days of normal practice/workouts �Took place in AWC for volleyball �Took place in Rockbowl for soccer �Trials were conducted immediately after practice

Procedure �Half of the trial were followed by PNF stretching (2, 4, 6) �Other half was without PNF stretching (1, 3, 5) �On the stretching days, we split up the participants to ensure more accurate results Stay warm and loose

Results �Mean scores were found for each participant �A Dependent Samples T-test was conducted Non- stretching mean: M=35. 84 cm PNF stretching mean: M=37. 35 cm There was a significant difference ▪ P value: 0. 001 and T value: -3. 916

Dependent Samples T-Test No Stretching Mean Standard Deviation 35. 8403 9. 9618 Degrees of Freedom 23 PNF Stretching 37. 3472 9. 35930 T-value P-value -3. 916 . 001

The Effects of PNF Stretching on Hamstring Flexibility in Female Collegiate Soccer and Volleyball Players 37, 8 37, 3 36, 8 Sit and Reach Scores (cm)36, 3 35, 8 35, 3 34, 8 No Stretching Mode PNF Stretching

Results �Two Independent Sample T-tests were conducted Test 1: to determine if significant difference in scores before PNF stretching ▪ Mean score for soccer players: M= 36. 97 cm ▪ Mean score for volleyball players: M=34. 71 cm ▪ Significant difference not was found (P=0. 473, t=. 548)

Independent Samples T-Test (no stretching) Mean Standard Deviation Degrees of Freedom Soccer 36. 9722 8. 991 22 Volleyball 34. 7083 11. 130 T-value P-value . 548 . 473

Results Test 2: to determine if difference in scores after PNF stretching ▪ Mean score for soccer players: M=38. 53 cm ▪ Mean score for volleyball players: M=36. 12 cm ▪ Significant difference was not found (p=0. 400, t=. 609)

Independent Samples T-Test (PNF stretching) Mean Standard Deviation Degrees of Freedom Soccer 38. 5278 2. 534 22 Volleyball 36. 1667 2. 930 T-value P-value . 609 . 400

Conclusion �Accept hypothesis 1 -PNF stretching increased ROM �This agrees with Silva et al. (2012), as they found that PNF stretching promotes a greater range of motion.

Conclusion Cont. �Reject hypothesis 2 -Female soccer players had higher V Sit and Reach results than volleyball players. However, this difference was not significant.

Extraneous Variables �Weather conditions �Intensity levels �Efficiency of data collection �Soreness of athlete

Future Studies �Longer study duration �More participants �Smaller test administrator to participant ratio �Male study

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