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 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 and 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 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   Mean Standard Deviation Degrees of Freedom T-value P-value No Stretching 35.8403 9.9618 23 -3.916 .001 PNF Stretching 37.3472 9.35930

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= 36.97cm Mean score for volleyball players: M=34.71cm Significant difference not was found (P=0.473, t=.548)

Independent Samples T-Test (no stretching)   Mean Standard Deviation Degrees of Freedom T-value P-value Soccer 36.9722 8.991 22 .548 .473 Volleyball 34.7083 11.130

Results Test 2: to determine if difference in scores after PNF stretching Mean score for soccer players: M=38.53cm Mean score for volleyball players: M=36.12cm Significant difference was not found (p=0.400, t=.609)

Independent Samples T-Test (PNF stretching)   Mean Standard Deviation Degrees of Freedom T-value P-value Soccer 38.5278 2.534 22 .609 .400 Volleyball 36.1667 2.930

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. most of the other works of literature in this area have shown that PNF stretching increases flexibility Believe vball would be higher due to their sport specific movements. Hard to verify-sample so small so not generalizable to larger population PRACTICAL APPLICATION FOR US KNOW PNF STRETCHING HELPS

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 For more reliable results we feel we should conduct this experiment again in a controlled setting-comparison

Future Studies Longer study duration More participants Smaller test administrator to participant ratio Male study Not generalizable-need larger population. Ratio: help with efficiency

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