Under the Gun: Percussive Massage Therapy and Physical and Perceptual Recovery in Active Adults

We adopted a repeated-measures, single-group design that implemented an experimental leg (massage gun recovery [GUN]) and a control leg (passive recovery [CON]). Participants were allocated experimental and control legs in a randomized, counterbalanced design. They completed physical and perceptual measures at various times before and after lower limb exercise and after the recovery intervention (Figure 1). Participants completed all testing within a 1.5-hour period and were asked to refrain from strenuous lower body exercise for 24 hours before and 24 hours after the study to limit any influence on physical testing or muscle soreness measures.

A total of 65 active young adults (age = 21.3 ± 1.4 years; age range = 18–30 years; 34 women: height = 165.8 ± 6.1 cm, mass = 66.0 ± 7.4 kg; 31 men: height = 181.1 ± 6.0 cm, mass = 81.5 ± 11.8 kg) volunteered. Participants were recruited through a university sport science undergraduate program. All volunteers were active in regular physical exercise sessions (approximately 3 times per week) and were free from lower limb injuries (hip, knee, or ankle) that might have affected their ability to perform the physical tests or exercise protocol. All participants provided written informed consent, and the study was approved by the La Trobe University Human Research Ethics Committee.

Before the testing session, participants rated their perception of whether “massage guns will improve recovery following exercise” on a continuous, 10-cm visual analog scale, ranging from strongly disagree (0 cm) to strongly agree (10 cm). Participants were then categorized as having high belief or low belief based on a cut-off of 5 cm on this scale, as used previously.¹³  Care was taken throughout the testing session to not influence participants’ perceptions of the use of massage guns.

The weight-bearing lunge test (WBLT) was performed as a measure of dorsiflexion range of motion of each ankle at baseline and after recovery. Previous investigators have reported robust interrater and intrarater reliability associated with the assessment of WBLT performance in healthy adults, with high levels of test-retest reliability demonstrated (standard error of measurement [SEM] = 1.1°, 95% CI = ±2.2°).¹⁴  The baseline measurement was collected after a dynamic warm-up consisting of 5 minutes of single- and double-legged calf raises, ballistic bounces, and ankle circles. Participants placed the foot along a measuring tape that was secured to the floor and aligned perpendicular to a wall, with both the toe and heel on the center line of the measuring tape. They were then instructed to progressively move the toe farther back from the wall on the measuring tape, repeating the lunge movement until the maximum distance at which they could tolerably lunge their knee to the wall without lifting the heel. Using the tape measure, we determined the distance from the tip of the big toe to the wall (in centimeters).

A nonstretch anthropometric measuring tape (model Lufkin Executive Thinline) was used to measure the circumference of the lower leg at baseline and after recovery. This measurement allowed assessment of any lower limb swelling associated with the exercise recovery intervention. The landmark was the widest girth of the calf muscle. A permanent marker was used to indicate the measurement site and ensure high levels of test-retest reliability across time (Figure 1). This method of assessing calf circumference has been shown to have high reliability (SEM = 0.5–0.6 cm; intraclass correlation coefficient [ICC] = 0.97)¹⁵  and to correlate with muscle volume (R² = 0.42).¹⁶ 

A custom-built isometric calf-raise rig housing a dual force-platform system (model FDLite Dual Force Platform; VALD Performance; Figure 2A) was used to obtain left- and right-leg isometric strength measurements at baseline, postexercise, and postrecovery. This method has demonstrated high reliability (ICC = 0.94; coefficient of variation = 6.1%) for bilateral assessment of plantar-flexion strength.¹⁷  Participants were seated on an adjustable-weight bench centered between the force platforms and maintained hip and knee flexion at 90° with their feet hip-width apart and centered on each platform. A soft foam pad was placed over their knees for comfort during testing. The researcher (A.J.L.) then adjusted the metal bar until it was firmly resting on the foam pad centered over the knees and secured the bar position with crocodile pins on the racking system. The bar height was recorded and repeated for subsequent testing. Participants were instructed to cross their hands over their shoulders and maintain an upright, vertical posture during isometric calf-raise testing. They were directed to perform maximal plantar flexion, pushing against the foam pad on top of their knees (Figure 2B) after an oral “3, 2, 1” countdown, as described earlier.^18,19  Before the first test, participants completed 2 warm-up efforts corresponding to 50% and 75% effort to familiarize themselves with the movement and bar position. They then performed 3 maximal isometric calf raises, holding each for 3 seconds, with a 10-second rest between raises. They were orally encouraged in the same manner during each repetition to exert maximal force production. Data were recorded using ForceDecks (VALD Performance) software and split into bilateral data obtained from each person’s left and right limbs for analysis.

A single-legged calf-raise test to exhaustion was performed pre-exercise (baseline) and postrecovery to assess the strength endurance of the calf muscles. The calf raises were completed in time with a metronome set at 60 beats per minute, with a 1-minute rest between limbs. The testing order for each leg (CON versus GUN) was randomized across participants but was kept the same for each individual. Starting position involved the participant standing on 1 limb, with the ankle in neutral position (0°) and the knee at full extension. The individual was instructed to complete as many repetitions of a single-legged calf raise (as high as possible or maximum range of motion) as possible. Using the fingers on a wall to balance was allowed but without applying any downward pressure on the wall to assist the movement. The 2 criteria for terminating the test were not completing a full range-of-motion calf-raise repetition in time with the metronome or volitional exhaustion. The test-retest reliability of the calf-raise test has been described in healthy adults and deemed highly reliable, with ICCs ranging from 0.78 to 0.99 and SEMs ranging from 2 to 6 repetitions.^20–25 

Participants rated their perceived muscle soreness for each limb on a scale of 1 (no soreness) to 10 (maximal soreness).²⁶  Ratings were obtained while they performed a single-legged calf raise on each side. For the 4-, 24-, and 48-hour postrecovery times, each person was sent an electronic survey link (QuestionPro) via anonymized text message, which contained the same instructions for completing the perceived muscle soreness scale for each limb.

The exercise bout used to induce fatigue and subsequent muscle soreness was targeted at the calf muscles. Participants were instructed to complete 3 sets of 20 double-legged calf raises at full range of motion off a 30-cm-high platform in time with a metronome set at 60 beats per minute and with a 1-minute rest between sets. They were allowed to use their fingers on a wall to balance but not to apply any downward pressure on the wall to assist their movement.

Immediately after the postexercise testing time point, participants performed a recovery intervention on 1 limb (GUN) while the other limb had no recovery intervention (CON). The recovery intervention involved a 5-minute treatment to the calf muscles using a massage gun device (Hydragun) with a soft attachment head. The massage gun device was used at a speed of 53 Hz, or approximately 3200 rpm, as reported previously.⁶  Participants were instructed to apply the massage gun to a relaxed calf muscle while seated. The medial gastrocnemius was the focus for the first half of the 5 minutes of the massage treatment and then the lateral gastrocnemius muscle for the second half. As per the manufacturer’s instructions, they were directed to “glide” the massage gun along the muscle belly continuously at the selected device speed.²⁷  After the 5-minute treatment, participants remained seated for a further 15 minutes before performing the postrecovery tests (Figure 1).

Descriptive statistics (means and SDs) for the WBLT (in centimeters), calf circumference (in centimeters), isometric net peak force (in newtons), isometric net force at 100 and 200 milliseconds (in newtons), calf-raise repetitions (number), and perceived muscle soreness (in arbitrary units [AUs]) were computed for the various times. A linear mixed model (LMM) was conducted to examine the effects of the recovery intervention (GUN versus CON) on these measures. The LMM consisted of a fixed effect of time (2 to 6 levels, depending on the variable) and a random intercept for participant identifier. We assessed normality via a visual inspection of a Q-to-Q plot and deemed the residuals to approximate a normal distribution. No interaction effect was recorded for time × intervention for any of the testing measures; thus, the model was refit without the interaction term. The mean differences in the outcomes from baseline level to each time were calculated, and 95% CIs were calculated to denote the imprecision of model parameter estimates.

A sensitivity analysis via a 2-way repeated-measures analysis of variance was also computed to ensure that the results of the LMM were robust. All data are presented as mean ± SD unless otherwise stated. In addition, we determined effect size statistics to evaluate differences between the GUN and CON groups at each time. For these measures, the standardized change in mean between times was identified and expressed as standardized (Cohen d) effects and 95% CIs. The magnitude of each effect size was interpreted using thresholds of 0.2, 0.5, and 0.8 for small, moderate, and large, respectively.²⁸  An effect size of <0.2 was considered trivial. Where the 95% confidence limits overlapped the thresholds for small positive and small negative values, the effect was considered unclear. All statistical analyses were conducted using the Jamovi statistical package (version 1.8.1; Jamovi Project, 2021), and P ≤ .05 indicated a difference.

We observed no interaction between group and time for perceived muscle soreness (F_5,582 = 1.69, P = .14). However, we found a main effect of time on perceived muscle soreness (F_5,591 = 64.77, P < .001), as perceived muscle soreness increased at each respective time compared with baseline. Perceived muscle soreness was greater by 2.5 AU (95% CI = 1.90, 3.08 AU; t₆₀₉ = 8.30; P < .001) at the 48-hour follow-up versus baseline. We noted a small difference in that perceived muscle soreness was greater in the GUN group compared with the CON group immediately postrecovery (−0.35 ± 0.35 AU) and at 4 hours postrecovery (−0.48 ± 0.39 AU; Figure 3).

The results of the 2-way repeated-measures analysis of variance for the remaining dependent variables were consistent with those of the LMM. No interaction was evident between group and time for the WBLT (F_1,126 = 0.317, P = .57, η²_p = 0.003), calf circumference (F_1,126 = 0.431, P = .51, η²_p = 0.003), and single-legged calf raises to exhaustion (F_1,126 = 0.494, P = .48, η²_p = 0.004), with unclear effect sizes (Table). In addition, we demonstrated no interaction between group and time for isometric peak net calf-raise force (F_1,122 = 0.0301, P = .97, η²_p = 0.000), isometric net vertical force at 100 milliseconds (F_1,122 = 0.124, P = .88, η²_p = 0.001), and isometric net vertical force at 200 milliseconds (F_1,122 = 0.00662, P = .94, η²_p = 0.001), with unclear effect sizes. However, a main effect of time was present for both calf circumference (F_1,126 = 39.409, P < .001) and calf endurance (F_1,126 = 26.604, P < .001). Specifically, calf circumference was greater at postrecovery (37.3 cm; range = 36.9–37.8 cm) than baseline (36.9 cm; range = 36.4–37.4 cm), and the number of calf raises completed was lower at postrecovery (n = 34; range = 31–36) than baseline (n = 39; range = 36–41).

When we categorized participants by their belief in the effectiveness of massage guns as a recovery intervention, 46 respondents (70.8%) had high belief (>5 cm on the visual analog scale) compared with 17 (26.2%) who had low belief (≤5 cm on the visual analog scale); 2 participants did not provide a response to this question. No main effect of belief on perceived muscle soreness was recorded.

The purpose of our study was to evaluate the effects of a short application of a massage gun to the calf muscles on perceptual and physical recovery after strenuous lower body exercise. A 5-minute application of a commercially available massage gun immediately after an exercise task had little effect on measures of ankle range of motion, calf circumference, isometric strength, or calf endurance. However, the use of these devices for acute recovery may result in a small increase in perceived muscle soreness in the 4 hours after use, although this finding was not statistically significant. In addition, we observed no effect of prior belief in the effectiveness of massage guns on their effectiveness for recovery. To our knowledge, we are the first to report on the use of massage guns immediately after strenuous lower limb bodyweight resistance exercise, showing they may have limited effect on perceived muscle soreness and other measures of performance recovery over a short-term timeframe.

Our main outcome was that massage guns did not appear to improve physical recovery after intense lower body exercise compared with a passive control condition. This result agrees with that of Alonso-Calvete et al,⁹  who observed no change in perceived fatigue and blood lactate with the use of a massage gun for 8 minutes after simulated water rescues in lifeguards. Although not directly comparable, similar investigations with 10 to 30 minutes of massage therapy immediately after strenuous running also demonstrated no effect on muscle soreness or muscle function (squat and drop jumps)²⁹  and no effect on quadriceps flexibility, isometric knee-extensor strength, or perceived fatigue.³⁰  In comparison, vibrating foam rollers improved range of motion, countermovement jump height, and muscle soreness after eccentric lower body exercise,^31,32  which may be related to increased body temperature and improved blood flow. Specific to our study, a 5-minute application of a massage gun appeared to offer no benefit in the recovery of calf muscle strength, range of motion, and endurance compared with a control condition of 20 minutes of passive recovery. Although this is a short timeframe in which to apply the selected recovery intervention and complete post-testing, it is also consistent with the recommended timing of use directed by massage gun manufacturers (eg, ≤2 minutes per muscle group at 1 time³³ ), despite the unclear basis for this recommendation. Presently, insufficient evidence is available to recommend the short-term use of massage guns for the recovery of lower limb range of motion, strength, and endurance after strenuous exercise versus a rest condition. As such, these devices may not be an ideal recovery intervention between lower body training sessions on the same day. However, whether this acute use of massage guns may have a different effect on physical factors across a longer timeframe (eg, post-testing 24 hours later) is unknown. In the future, researchers could examine muscle blood flow and oxygen saturation with the use of massage guns, as has been done with vibrating foam rollers,³²  to further elucidate any physiological changes (or lack thereof) with these devices.

An unexpected observation in this study was the small increase in perceived muscle soreness observed immediately after recovery and 4 hours after recovery in the GUN group. In comparison, forms of vibration therapy such as vibrating foam rollers reduced perceived pain after fatiguing eccentric exercise, which may be related to increased local skin temperature and blood flow.³²  Yet handheld percussive massage therapy is distinct from both massage and vibration therapy in its amplitude, frequency, and direction of pressure, as the rapid and powerful stimulus can be applied in any direction at the will of the user. This more forceful manipulation of muscle tissues may stimulate mechanoreceptor nerve endings,³⁴  resulting in greater perceived muscle soreness immediately after application of the massage gun. However, this response appears to only be short term, as perceived muscle soreness at the 24- and 48-hour time points was not different between groups. It is also possible that the high frequency selected for the massage guns (approximately 53 Hz per Konrad et al⁶ ) was a factor in this small increase in perceived muscle soreness, as there may be individual variations in tolerance to massage gun speed and amplitude, which requires further investigation. Similarly, individuals demonstrated different pressure-pain thresholds and response patterns to traditional sport massage, which contributes to the perceived effectiveness of this recovery strategy.³⁵  Given that participants may not have been familiar with use of the massage guns and their effects, there is also the possibility that increased tolerance and reduced discomfort may occur with repeated use of the devices, as has occurred with deep-pressure massage.³⁶  Nonetheless, when considering this finding in conjunction with previous case reports of serious medical incidents from massage guns,^10,11  such devices should be used with caution and only as tolerated by the individual user.

Researchers investigating recovery interventions have previously considered the influence of prior belief on the effectiveness of the intervention.^13,37,38  One example involves compression socks, whereby runners who strongly believed in the effectiveness of compression socks displayed improved 5-km time trial performance after wearing the garments for recovery.¹³  In our study, almost three-quarters of the participants were categorized as having high belief in the effectiveness of massage guns as a recovery intervention. Coaches, fellow athletes, and websites, rather than research articles or practitioners,³⁷  are the main sources of recovery information and recommendations for athletes, which may explain the high belief in the effectiveness of these devices in the absence of scientific evidence. Despite this, we saw no significant changes in either perceptual or physical measures between those with high belief versus low belief. Although a positive psychological perception did not influence the effectiveness of massage guns in this case, it may be important to consider in future investigations as a means of explaining variances in responses among participants.

Several limitations should be considered when interpreting our results. First, given the scarcity of existing literature on massage guns, no consensus exists on ideal vibration speed or amplitude for their use and whether this may differ depending on the timing of use (eg, pre-exercise or postexercise). Additionally, the participants’ previous experience with massage guns was not obtained before testing, which may have influenced their use and perception of the devices during the recovery intervention. Second, participants’ dietary intake was not tracked or controlled before the study or during the 48-hour follow-up period, which may have influenced muscular recovery. It is also possible that a systemic healing response to strenuous exercise occurred and influenced the interpretation of results from a “control leg” and an “experimental leg.” Furthermore, perceived muscle soreness varies across muscle groups,³⁹  justifying the need for further examination of the application of massage guns after strenuous exercise targeting muscle groups other than the calf muscles.

Handheld percussive massage therapy is a relatively new and under-researched recovery tool that is intended to increase range of motion and reduce muscle soreness by delivering targeted vibration to soft tissues. Our findings indicate that massage guns had little effect on measures of ankle range of motion, calf circumference, isometric strength, or calf endurance when applied for 5 minutes after an intense bout of calf exercise. Moreover, small increases may occur in perceived muscle soreness up to 4 hours after use, although the finding was not statistically significant. Therefore, caution may need to be taken when considering the application of these devices for lower body recovery immediately after strenuous exercise if the focus of recovery is to improve physical, perceptual, or both measures in preparation for subsequent exercise.

We thank Ketha Ledchumanasarma for his assistance with photography.