Menthol-Based Topical Analgesic Induces Similar Upper and Lower Body Pain Pressure Threshold Values: A Randomized Trial.

CONTEXT: Both health professionals and consumers use menthol-based topical analgesics extensively for the temporary relief of pain from musculoskeletal ailments or injury. However, there are no reports of differences in the pain pressure threshold (PPT) or the relative effectiveness of topical analgesics to reduce pain in the upper and lower body muscles and tendons. The objective of this study was to investigate whether differences existed in PPT and relative pain attenuation associated with a menthol-based topical analgesic over a variety of upper and lower body muscles and tendons. DESIGN: Randomized allocation, controlled, intervention study. METHODS: Sixteen participants (10 females and 6 males) were tested on their dominant or nondominant side. The order of specific muscle/tendon testing was also randomized, which included upper body (middle deltoid, biceps brachii, and lateral epicondylar tendon) and lower body locations (quadriceps, hamstrings, gastrocnemius, lumbosacral erector spinae muscles, and patellar and Achilles tendons). The PPT was monitored before and 15 minutes following the application of a menthol-based topical analgesic. RESULTS: A menthol-based topical analgesic increased PPT (decreased pain sensitivity) overall (P = .05; 11.6% [2.4%]; d = 1.05) and PPT was higher (P < .0001; 31.5%-44.2%; d = 1.03-1.8) for lower versus upper body locations. CONCLUSIONS: Health professionals and the public can be assured of similar reductions in pain sensitivity independent of the location of application of a menthol-based topical analgesic.

Lack of Evidence for Non-Local Muscle Fatigue and Performance Enhancement in Young Adults.

Post-activation performance enhancement (PAPE) is an improvement to voluntary muscle performance following a conditioning activity. There is evidence of fatigue resistance deficits in non-exercised muscles following unilateral fatiguing exercise of a contralateral muscle. The purpose of this study was to determine if a unilateral conditioning exercise protocol could induce PAPE in a contralateral, non-exercised muscle in young healthy adults. Thirty-two recreationally trained (n = 16) and athletically trained (n = 16) participants (16 males; age: 22.9 ± 2.03 years; height: 1.81 ± 0.06 m; weight: 82.8 ± 9.43 kg, and 16 females; age: 23.1 ± 2.80 years; height: 1.67 ± 0.07 m; weight: 66.4 ± 11.09 kg) were randomly allocated into two groups (dominant or non-dominant limb intervention). The experimental intervention, involved a conditioning exercise (4-repetitions of 5-seconds knee extension maximal voluntary isometric contractions: MVIC) with either the dominant (DOM) (n = 16) or non-dominant (ND) (n = 16) knee extensors with testing of the same (exercised) or contralateral (non-exercised) leg as well as a control (no conditioning exercise: n = 32) condition. Testing was performed before, 1-minute and 10-minutes after a high intensity, low volume, conditioning protocol (2 sets of 2x5-s MVIC). Pre- and post-testing included MVIC force and F100 (force developed in the first 100 ms: a proxy measure of rate of force development) and unilateral drop jump (DJ) height and contact time. There were no significant MVIC peak force or EMG nor DJ height or contact time interactions (intervention x limb dominance x time). The pre-test (0.50 ± 0.13) dominant leg MVIC F100 forces exceeded (p = 0.02) both post-test and post-10 min by a small magnitude 8.7% (d = 0.31). There was also a significant (p = 0.02) time x intervention leg x testing leg intervention, although it was observed that the control condition was as likely to demonstrate small to large magnitude changes as were the dominant and non-dominant legs. Following the conditioning activity, there was no significant evidence for non-local improvements (PAPE), or performance decreases.

Acute Effects of Foam Rolling on Range of Motion in Healthy Adults: A Systematic Review with Multilevel Meta-analysis.

BACKGROUND: Foam rolling (FR) has been demonstrated to acutely enhance joint range of motion (ROM). However, data syntheses pooling the effect sizes across studies are scarce. It is, furthermore, unknown which moderators affect the treatment outcome. OBJECTIVE: To quantify the immediate effects of FR on ROM in healthy adults. METHODS: A multilevel meta-analysis with a robust random effects meta-regression model was used to pool the standardized mean differences (SMD) between FR and no-exercise (NEX) as well as FR and stretching. The influence of the possible effect modifiers treatment duration, speed, targeted muscle, testing mode (active/passive ROM), sex, BMI, and study design was examined in a moderator analysis. RESULTS: Twenty-six trials with high methodological quality (PEDro scale) were identified. Compared to NEX, FR had a large positive effect on ROM (SMD: 0.74, 95% CI 0.42-1.01, p = 0.0002), but was not superior to stretching (SMD: - 0.02, 95% CI - 0.73 to 0.69, p = 0.95). Although the few individual study findings suggest that FR with vibration may be more effective than NEX or FR without vibration, the pooled results did not reveal significant differences (SMD: 6.75, 95% CI - 76.4 to 89.9, p = 0.49 and SMD: 0.66, 95% CI - 1.5 to 2.8, p = 0.32). According to the moderator analysis, most potential effect modifiers (e.g., BMI, speed or duration) do not have a significant impact (p > 0.05) but FR may be less effective in men (p < 0.05). CONCLUSION: FR represents an effective method to induce acute improvements in joint ROM. The impact of moderators should be further elucidated in future research.

The Addition of Transcutaneous Electrical Nerve Stimulation with Roller Massage Alone or in Combination Did Not Increase Pain Tolerance or Range of Motion.

Roller massage (RM) can be painful and induce muscle activity during application. Acute increases in pain pressure threshold (PPT) and range of motion (ROM) have been previously reported following RM. It is unclear whether the RM-induced increases in PPT and ROM can be attributed to changes in neural or muscle responses. To help determine if neural pain pathways are affected by roller massage, transcutaneous electrical nerve stimulation (TENS) was utilized as a form of electroanalgesia during RM with PPT and ROM tested on the affected and contralateral quadriceps. The purpose of this study was to evaluate in both quadriceps, the effect of brief intense TENS on PPT and ROM following unilateral RM of the quadriceps. A randomized within subjects' design was used to examine local and non-local effects of TENS and roller massage versus a control condition (rolling without TENS application). Four 30s bouts of roller massage of the dominant quadriceps were implemented with 30s of rest. The researcher applied the RM using a constant pressure device with approximately 70% of the maximum tolerable load. Perceived pain was monitored using a visual analog scale (VAS) during RM. Ipsilateral and contralateral quadriceps ROM and PPT were measured immediately following RM. Significant main effects for time showed increased PPT and ROM in both the treated and contralateral quadriceps, with no significant main effects for intervention or interactions for intervention and time. Moderate to large effect sizes and minimal clinically important differences (MCID) were detected when comparing baseline to pre- and post-tests respectively. VAS scores were significantly (main effect for intervention) and near significantly (interactions) reduced with MCID when TENS was applied during rolling. The addition of TENS to rolling did not increase PPT or ROM in the affected or contralateral quadriceps, likely due to a repeated testing effect.