It is recognized that stretching is an effective method to chronically increase the joint range of motion. However, the effects of stretching training on the muscle-tendon structural properties remain unclear. This systematic review with meta-analysis aimed to determine whether chronic stretching alter the muscle-tendon structural properties. Published papers regarding longitudinal stretching (static, dynamic and/or PNF) intervention (either randomized or not) in humans of any age and health status, with more than 2 weeks in duration and at least 2 sessions per week, were searched in PubMed, PEDro, ScienceDirect and ResearchGate databases. Structural or mechanical variables from joint (maximal tolerated passive torque or resistance to stretch) or muscle-tendon unit (muscle architecture, stiffness, extensibility, shear modulus, volume, thickness, cross-sectional area, and slack length) were extracted from those papers. A total of 26 studies were selected, with a duration ranging from 3 to 8 weeks, and an average total time under stretching of 1165 seconds per week. Small effects were seen for maximal tolerated passive torque, but trivial effects were seen for joint resistance to stretch, muscle architecture, muscle stiffness, and tendon stiffness. A large heterogeneity was seen for most of the variables. Stretching interventions with 3- to 8-week duration do not seem to change either the muscle or the tendon properties, although it increases the extensibility and tolerance to a greater tensile force. Adaptations to chronic stretching protocols shorter than 8 weeks seem to mostly occur at a sensory level.

Context: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.Objective:To investigate the acute effects of hold–relax proprioceptive neuromuscular facilitation (PNF) with and without vibration therapy on internal rotation in individuals with GIRD.Design:2-within (stretch × time) comparison with repeated measures.Setting:Controlled laboratory.Participants: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.Interventions: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).Results:There was a stretch-by-time interaction (F2,20 = 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.Conclusions: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.

Invited Commentary on: ‘The use of proprioceptive neuromuscular facilitation in physiotherapy practice’, Westwater-Wood et al. The recent narrative review by Westwater-Wood et al. highlights many of the issues we are currently attempting to come to terms with in our own research group: what types of proprioceptive neuromuscular facilitation (PNF) are currently in use; how are the protocols defined; what are their effects; and, what are the underlying mechanisms encouraging these effects? Bravely, Westwater-Wood et al. imply that current physiotherapy practice is largely informed by tradition and not evidence, be that clinical or experimental, and that current PNF practice and curricula are indicative of that tradition. The two primary categories within the umbrella descriptor of PNF are strength and stretch. Most simply put, in the former, the therapist and client work together to try and (re)establish functional muscle contraction; in the latter, they work towards increasing range of motion (ROM). Both PNFs are said to gain efficacy through a synergistic stimulation and recruitment of the neuromuscular proprioceptors. PNF has spread from its original position as a rehabilitative modality within physiotherapy to become recognized as the most effective stretching technique used in sports training. Along the way, many changes to the original protocol envisaged by Kabat, and still promoted through texts such as Voss et al., have occurred. When performed following the PNF protoco

The relationship between isometric contraction durations and improvement in shoulder joint range of motion. Proprioceptive Neuromuscular Facilitation (PNF) flexibility techniques are now being used in health and sports related activities, yet it is unclear as to the relationship between various isometric contraction time increments and joint range of motion. The purpose of this study, therefore, was to determine the relationship between a three-second, six-second, and ten-second maximum voluntary isometric contraction (MVIC). A modified PNF procedure referred to as the slow-reversal-hold-relax (SRHR) flexibility technique was employed in the investigation. It was hypothesized that longer MVIC time increments used with the SRHR flexibility technique would provide greater range of motion (ROM). Specifically, the ten-second MVIC was believed to be superior to the six-second and three-second MVIC. Furthermore, it was hypothesized that the six-second MVIC was superior to the three-second MVIC. Sixty subjects, ages 14-57 were randomly assigned to one of three treatment groups.

Proprioceptive Neuromuscular Facilitation (PNF) has deep roots in neurological rehabilitation for the treatment of neuromuscular disorders that has carried over into musculoskeletal rehabilitation and human performance. There are two major aspects of PNF in musculoskeletal practice, stretching and strengthening, but this commentary only addresses the effects of strengthening. Techniques that do not incorporate all the original principles and guidelines as described in the literature are often miscategorized as PNF. The purpose of this clinical update/commentary is to review the essential principles, guidelines, and techniques for the effective utilization of PNF strengthening exercises for the upper extremity highlighting the importance of regaining/maintaining the synergist relationship between the glenohumeral joint and scapula. It will also provide recommended sequencing, exercise parameters, and present evidence of the effectiveness of incorporating PNF patterns into the rehabilitation programs for upper extremity pathologies. # Level of Evidence 5.

types of contractions: isometric, iso- tonic, and isokinetic. ISOMETRIC Isometric exercise occurs when … pare the athlete for activity. Proprioceptive neuromuscular facilitation (PNF) is a special rehabilitation … sur- rounding soft tissue. 7. Proprioceptive neuromuscular facilitation is the use of the stretch reflex

types of contractions: isometric, iso- tonic, and isokinetic. ISOMETRIC Isometric exercise occurs when … pare the athlete for activity. Proprioceptive neuromuscular facilitation (PNF) is a special rehabilitation … sur- rounding soft tissue. + 7. Proprioceptive neuromuscular facilitation is the use of the stretch reflex

Ipsilateral and contralateral effects of proprioceptive neuromuscular facilitation techniques on hip motion and electromyographic activity. The effects of two proprioceptive neuromuscular facilitation techniques on increasing the range of hip flexion during active straight leg raising were compared in 30 normal women. Subjects were randomly assigned into contract-relax, hold-relax, or control groups and were tested with the pelvis stabilized. An exercise technique was applied to the right lower extremity in two diagonal patterns while electrical activity was monitored from the contralateral rectus femoris, vastus medialis, semimembranosus, and biceps femoris muscles. Comparison of pretest and posttest measurements of the angle of straight leg raising of both lower extremities indicated that the increase in range of motion of the right lower extremity in subjects in the contract-relax group was significantly greater than that in the hold-relax and control groups. For the unexercised extremity, the increase in motion in subjects in the contract-relax group was significantly greater than that in the control group.