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Tuesday, June 6, 2023

Research Review: Effects of Foam Rolling and Stretching on Hip Flexion Range of Motion

Brent Brookbush

Brent Brookbush


Research Review: Effects of Foam Rolling and Stretching on Hip Flexion Range of Motion

By Jinny McGivern DPT, Certified Yoga Instructor

Edited by Brent Brookbush DPT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Mohr, A. R., Long, B. C., & Goad, C. L. (forthcoming 2014). Foam Rolling and Static Stretching on Passive Hip Flexion Range of Motion. Journal of sport rehabilitation. Currently in press. ABSTRACT

Foam Roll technique used in this study. Image courtesy of http://www.sportsister.com/online-courses/online-courses/2014/02/24/how-to-use-a-foam-roller/.

Why is this relevant?: Foam rolling is a commonly used intervention with clients in various setting form clinics, to health clubs, to athletic training facilities. There is limited research on the efficacy of this technique, and less research on how this technique may be used in conjunction with other interventions such as stretching. This research provides much needed data on the impact of foam rolling and static stretching on hip flexion passive range of motion (PROM).

Study Summary

Study Design Randomized Controlled trial
Level of Evidence 2b - Single Randomized Controlled Trial with small sample size
Subject Demographics
  • Age: 40 subjects randomized into 4  groups: Static stretching (SS) (age = 22.0 +/- 3.8 yrs); Foam Rolling (FR) (age 21.0 +/-2.21 yrs); Foam Rolling & Static Stretching (FRSS) (21.2 +/- 2.44 yrs); Control (CON) (age = 20.8 +/- 2.7)
  • Gender: not reported
  • Characteristics: no previous history of lower extremity or spine injury, no participation in flexibility program, no history of a condition limiting muscle flexibility or circulation,  recreationally active for 1 - 5 hours per week, limited hamstring flexibility (defined as passive straight leg raise < 90 degrees).
Outcome MeasuresChange in hip flexion passive range of motion (PROM) between pre-test on day 1 and post-test on day 6
  • Significant change in hip flexion PROM for all intervention groups from Day 1 to Day 6.
  • FRSS group demonstrated a significantly greater increase in PROM as compared to other groups.
  • There were no other significant differences between groups.
ConclusionsThere are several options for interventions to increase hip flexion PROM.   The combination of foam rolling and static stretching resulted in the greatest increase in PROM over a 2 week period.
Conclusions of the ResearchersYoung uninjured individuals, with hip flexion ROM less than 90 degrees, may experience a greater benefit from a combination of foam rolling and static stretching as opposed to either of these activities performed in isolation when attempting to increase hip flexion PROM.

Hamstrings - http://img.breakingmuscle.com

Review & Commentary:

The authors of this study utilized a specifically defined group of subjects with clearly established inclusion/exclusion criteria. Other strong points in the design include - random assignment of subjects into each of the 4 groups and the use of a control group which could be measured against. The researchers established standard procedures for measurements including: securing the subject's position on the table with straps (straps placed superior to patella on non tested lower extremity & over anterior superior iliac spine ); utilizing a measurement tool with high intra-rater reliability (bubble goniometer - intra-rater ICC .92-.97), and implementing a standard procedure to ensure consistent placement of the tool. With respect to the intervention, the authors created a specific protocol for the foam roll technique, rolling superior to inferior from ischial tuberosity to popliteal fossa, at a pace of one length per second (using a metronome). The dosage of the intervention was set at 3 bouts - foam rolling for 1 minute with 30s rest in-between bouts, stretching held for 1 minute with a 30s rest in-between bouts, or both. For the FRSS group, foam rolling was always performed prior to static stretching . The researchers ensured that their subjects were familiar with study procedures; however, practice of the foam rolling technique was not permitted for fear that this would affect outcomes - if some subjects "practiced" more than others it may have resulted in an uncontrolled increase in dose. Instead, subjects received visual demonstration and verbal explanation.

The researchers assessed hip flexion PROM and only included those with less than 90 degrees of hip flexion (straight leg measurement). Testing for limited ROM as part of the inclusion criteria, is an important and often overlooked parameter in stretching research. Subjects with hyper-mobility may have confounded results as they respond differently to treatment, or not at all. Additionally by selecting this group of individuals the authors are singling out static stretching as a specific intervention to increase ROM, rather than an intervention that is arbitrarily applied to "improve performance" without understanding if ROM is a factor in limiting performance. A larger discussion of the limitations of static stretching research is included in the article "What can we learn from Static Stretching research?"

Like all research, this study is not without its limitations. In particular, the small and homogeneous sample group (40 young healthy subjects) with only 10 subjects per group. A larger sample size would be beneficial, as well as, studies on various populations. It is impossible to know if gains in flexibility persisted beyond the end of the 2 week intervention, as there was not long-term follow up. It would have been helpful if the researchers reported the baseline PROM measurements for each group and reported on whether or not there were significant differences between groups at baseline which could have impacted results. When carrying out measurements as well as the stretching intervention, the examiner performed a passive straight leg raise to point of "subject discomfort without pain". This aspect of the methodology appears to lack standardization. Each subject's perception of discomfort and amount of discomfort that was appropriate may have been different. A standardized or visual analog scale may have been useful to allow each subject to quantify discomfort. This may have improved consistency in determining the stopping point for the stretch/measurement.

The authors hypothesize that their subjects saw the greatest gains in PROM with the foam rolling/static stretching combination because of an increase in surface tissue temperature (possibly due to increased circulation from massage), as well as, changes in myofascial structures (thixotropic properties). This lead to reduced tissue viscosity when stretch was applied and allowed greater gains in PROM.

The authors point out that there is a lack of consensus among researchers on the effect foam rolling has on tissues and how a foamroll should be used. They make mention of another study (Miller & Rockney, 2006 - not reviewed by this site), with a similar protocol to theirs that found no effect of foam rolling on hip flexion ROM. A key methodological difference between these studies, as explained by Mohr et. al, is outcomes based on active knee extension compared to the passive straight leg raise used in this study. What does this mean? Does foam rolling affect structures that contribute to restrictions of passive motion, but has less impact on neural drive, neuromuscular control and reciprocal inhibition? Would foam rolling and stretching, followed by active neuromuscular re-education result in greater gains in active ROM?

Why is this study important?

This study is important because it provides information on how a specific, commonly used intervention effects human movement when applied to a specific group of individuals.

How does it affect practice?

As human movement professionals, we are constantly seeking new methods of improving our client's outcomes and assisting them in achieving their goals.

The article informs us that while foam rolling, static stretching and a combination of foam rolling and static stretching all increase PROM, the combination of the two results in the greatest gains. We can use this information to refine practice, improving the efficacy and efficiency of our practice.

How does it relate to Brookbush Institute Content?

The Brookbush Institute utilizes a combination of a foam roll technique followed by a stretch technique (as developed by the National Academy of Sports Medicine) in its corrective exercise program designs. While this sequence is similar to the intervention described in this article, it is important to note that the type of foam roll technique utilized by the Brookbush Institute differs from the technique utilized in this study. Instead of using the foam roller as a method of self massage, the Brookbush Institute utilizes it as a vehicle for self-administered trigger point release - a technique that consists of locating the most tender point in a muscle and sustaining pressure on this point until relaxation and a reduction of pain occur (approximately 30s) with the intention of reducing irritability and hypertonicity. Although this protocol differs from the one used in this study, the study does support the order that has been previously proposed by the National Academy of Sports Medicine and adopted by the Brookbush Institute. For more information on self administered release techniques utilized by the Brookbush Institiute refer to this article: Guidelines for Self Administered Release Techniques  and find all of the self-administered release techniques commonly used by visiting the section "Flexibility ."

The authors of this study utilized a passive straight leg raise to stretch the hamstrings. The Brookbush Institute does not tend to stretch the hamstrings as a group, but prefers to consider the biceps femoris (BF) discretely from semimembranosus/semitendinosus (SM/ST) . This separation is based on each muscle's different contribution to movement at the knee (BF = tibial external rotation; SM/ST = tibial internal rotation), as well as their propensity for overactivity versus underactivity respectively. Because BF has a propensity for overactivity, it is a candidate for inhibitory techniques, i.e. release and stretching techniques. Because SM/ST has a propensity for underactivity, it is a candidate for activation techniques, not release & stretch techniques. Additional information on the role of these muscles in postural dysfunction is described in the Lower Leg Dysfunction (LLD)  and Lumbopelvic Hip Dysfunction (LPHCD) Models in the section Postural Dysfunction/Movement Impairment . Videos below provide information on the self-administered trigger point release techniques and stretching for BF , as well as more information on when it is desirable to stretch the hamstrings.

When Do We Stretch the Hamstrings

Biceps Femoris SA Static Release

Biceps Femoris SA Active Release

Biceps Femoris Active Stretch

Dynamic Biceps Femoris (Lateral Hamstring) Stretch

© 2014 Brent Brookbush

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