performance can be associated with the magnitude of the JPS. 4 Therefore, interventions to enhance the JPS would be concerns in the area of athletic training and sports science. Proprioceptive neuromuscular facilitation (PNF) can be a promising intervention, and several studies have investigated this subject
Hiroshi Takasaki, Yu Okubo and Shun Okuyama
Allyson M. Carter, Stephen J. Kinzey, Linda F. Chitwood and Judith L Cole
Proprioceptive neuromuscular facilitation (PNF) is commonly used before competition to increase range of motion. It is not known how it changes muscle response to rapid length changes.
To determine whether PNF alters hamstring muscle activity during response to rapid elongation.
2 X 2 factorial.
Twenty-four women; means: 167.27 cm, 58.92 kg, 21.42 y, 18.41% body fat, 21.06 kg/m2 BMI.
Measurements before and after either rest or PNF were compared.
Main Outcome Measures:
Average muscle activity immediately after a rapid and unexpected stretch, 3 times pretreatment and posttreatment, averaged into 2 pre-and post- measures.
PNF caused decreased activity in the biceps femoris during response to a sudden stretch (P = .04). No differences were found in semitendinosus activity (P = .35).
Decreased muscle activity likely results from acute desensitization of the muscle spindle, which might increase risk of muscle and tendon injury.
Reed Ferber, Denise C. Gravelle and Louis R. Osternig
The effects of proprioceptive neuromuscular facilitation (PNF) on joint range of motion (ROM) for older adults are unknown, and few studies have investigated changes in joint ROM associated with age. This study examined PNF stretch techniques' effects on knee-joint ROM in trained (T) and untrained (UT) older adults. Knee-joint ROM was tested in T and UT adults age 45–55 and 65–75 years using 3 PNF stretch techniques: static stretch (SS), contract-relax (CR). and agonist contract-relax (ACR). The 45–55 UT group achieved significantly more ROM than did the 65–75 UT group, suggesting an age-related decline in ROM. The 65–75 T group achieved significantly greater knee-extension ROM than did their UT counterparts, indicating a training-related response to PNF stretch techniques and that lifetime training might counteract age-related declines in joint ROM. The ACR-PNF stretch condition produced 4–6° more ROM than did CR and SS for all groups except the 65–75 UT group, possibly as a result of lack of neuromuscular control or muscle strength.
Che-Hsiu Chen, Tsun-Shun Huang, Huei-Ming Chai, Mei-Hwa Jan and Jiu-Jenq Lin
Recent studies have shown that the static stretch (SS) may adversely affect leg-muscle performance.
The authors examined the short-term effects of 2 stretching exercises on hamstrings muscle before and after exercise.
9 healthy, physically active men.
There were 3 protocols in a randomized order with a 7-d interval: nonstretching (CON protocol), hamstrings static stretching (SS) with proprioceptive neuromuscular facilitation (PNF), and SS with kinesio-taping application on the hamstrings.
Main Outcome Measures:
Outcome measures included first-felt and maximum tolerant-felt range of motion (FROM and TROM), maximal knee-flexion peak torque (PT) at 180°/s, and hamstrings muscle stiffness.
Groups were not different at prestretching in terms of hamstrings flexibility, PT, and muscle stiffness. At poststretching, both stretching protocols showed significant increases in FROM and TROM (P < .05). Stiffer hamstrings muscle and decreased PT were found in both SS+PNF and CON protocols (P < .05). However, there was no significant difference in the SS+Taping protocol (P > .05).
The stretching protocols improve hamstrings flexibility immediately, but after exercise hamstrings peak torque is diminished in the SS+PNF but not in the SS+Taping group. This means that SS+Taping can prevent negative results from exercise, which may prevent muscle injury.
Jennifer A. Stone
Kristian J. Hill, Kendall P. Robinson, Jennifer W. Cuchna and Matthew C. Hoch
Increasing hamstring flexibility through clinical stretching interventions may be an effective means to prevent hamstring injuries. However the most effective method to increase hamstring flexibility has yet to be determined.
For a healthy individual, are proprioceptive neuromuscular facilitation (PNF) stretching programs more effective in immediately improving hamstring flexibility when compared with static stretching programs?
Summary of Key Findings:
A thorough literature search returned 195 possible studies; 5 studies met the inclusion criteria and were included. Current evidence supports the use of PNF stretching or static stretching programs for increasing hamstring flexibility. However, neither program demonstrated superior effectiveness when examining immediate increases in hamstring flexibility.
Clinical Bottom Line:
There were consistent findings from multiple low-quality studies that indicate there is no difference in the immediate improvements in hamstring flexibility when comparing PNF stretching programs to static stretching programs in physically active adults.
Strength of Recommendation:
Grade B evidence exists that PNF and static stretching programs equally increase hamstring flexibility immediately following the stretching program.
W. Steven Tucker and Stephen W. Slone
Clinicians use various stretching techniques to prevent the onset of and treat glenohumeral internal-rotation deficit (GIRD). It is unknown which stretching technique is the most effective.
To investigate the acute effects of hold–relax proprioceptive neuromuscular facilitation (PNF) with and without vibration therapy on internal rotation in individuals with GIRD.
2-within (stretch × time) comparison with repeated measures.
11 male current and former overhead athletes (19.8 ± 1.4 y, 184.5 ± 4.5 cm, 91.8 ± 11.6 kg) who presented with GIRD.
At 3 separate sessions, participants performed 1 of 3 randomly assigned stretches: hold–relax PNF (PNF), hold–relax PNF in combination with a whole-body-vibration unit set at 30 Hz (PNF-V), and static stretch (SS). Pretest and posttest maximum passive glenohumeral internal-rotation measurements were taken with a digital protractor.
Main Outcome Measures:
The dependent variables were the mean glenohumeral internal-rotation measurements taken at the pretest and posttest. The influence of stretch (PNF, PNF-V, and SS) and time (pretest and posttest) on mean glenohumeral internal rotation was compared using a 3 × 2 factorial ANOVA with repeated measures on both variables (P ≤ .05).
There was a stretch-by-time interaction (F 2,20 = 34.697, P < .001). Post hoc testing revealed that the PNF posttest (73.0° ± 10.4°) was greater than the PNF pretest (60.0° ± 11.8°), the PNF-V posttest (74.7° ± 10.0°) was greater than the PNF-V pretest (57.4° ± 10.4°), and the SS posttest (67.0° ± 10.7°) was greater than the SS pretest (60.1° ± 9.4°). When comparing the posttest values, the PNF-V posttest was greater than the SS posttest.
All 3 stretches (PNF, PNF-V, and SS) resulted in acute increases in glenohumeral internal rotation in individuals presenting with GIRD. The PNF-V stretch resulted in the greatest increase and would be the most clinically beneficial for patients with GIRD.