Specific and cross-over effects of foam rolling on ankle dorsiflexion range of motion
Kelly S. Beardsley C. International Journal of Sports Physical Therapy. 2011, 11(4); 544-551.
Take Home Message:
Foam rolling may lead to small improvements in dorsiflexion range of motion in the contralateral limb.
Flexibility training is a typical recommendation for healthcare professionals and strength coaches. Static stretching has a cross-over effect to the contralateral limb
but it is unclear if foam rolling elicits the same effect. Therefore, the authors conducted a randomized trial to examine mechanical effects and neurological cross-over effects of foam rolling on dorsiflexion among 26 recreationally active college students (16 male and 10 female). Participants were randomly assigned to either a foam rolling group (13 participants) or control group (13 participants). All participants performed 10 double-leg heel raises as a warm up before testing. The authors measured baseline ankle dorsiflexion range of motion (ROM) using the weight bearing lung test. The foam rolling group then rolled the calf musculature of the dominant leg for 3 bouts of 30 seconds (10 seconds rest between bouts). Participants applied as much force as could be tolerated to the roller. Participants were directed to focus on the 3 aspects of the calf (lateral, middle, and medial). The control group simply rested for 2 minutes. Next, the authors recorded ankle dorsiflexion changes at 5-minute intervals over a 20-minute period. Overall, the authors found no difference between groups. However, only members of the foam rolling group had increased dorsiflexion compared with baseline. The actual change in ankle ROM in the dominant leg was small (1.12cm / 8.79%) and even smaller in the non-dominant leg (0.72cm / 5.55%).
Cross-over effects are an important aspect of understanding our neuromuscular connections. The specific variables that influence these effects remain unclear. Although the authors identified foam rolling as a mechanical modality that has neurophysiological implications, the non-dominant leg received applied pressure by being crossed over the dominant leg during the foam rolling process. It would be interesting to see a foam rolling technique that can effectively treat a single leg without impacting the contralateral limb. The repeated testing could also have altered ROM due to stretch tolerance. Elite athletes may not benefit from such a small
cross-over effect. However, the implications may be more suitable for the general population, injured athletes, or those suffering from neurological disease. It would be interesting to see if the cross-over effects of foam rolling if people perform it daily over a longer time. In conclusion, clinicians should reiterate to their clients that a single bout of foam rolling can only produce minimal changes in ROM.    
Questions for Discussion: If foam rolling is a key variable in flexibility training, what are the “optimal” recommendations for time, duration, and pressure on the roller? What are the potential cross-over implications for immobilized joints?
Written by: Richard Shaw
Reviewed by: Jeffrey Driban
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Kelly S, & Beardsley C (2016). SPECIFIC AND CROSS-OVER EFFECTS OF FOAM ROLLING ON ANKLE DORSIFLEXION RANGE OF MOTION. International journal of sports physical therapy, 11 (4), 544-51 PMID: 27525179