Roller massage (RM) interventions have shown acute increases in range of motion (ROM) and pain pressure threshold (PPT). It is unclear whether the RM-induced increases can be attributed to changes in neural or muscle responses. The purpose of this study was to evaluate the effect of altered afferent input via application of RM on spinal excitability, as measured with the Hoffmann (H-) reflex. A randomized within-subjects design was used. Three 30-s bouts of RM were implemented on a rested, nonexercised, injury-free muscle with 30 s of rest between bouts. The researcher applied RM to the plantar flexors at three intensities of pain: high, moderate, and sham. Measures included normalized M-wave and H-reflex peak-to-peak amplitudes before, during, and up to 3 min postintervention. M-wave and H-reflex measures were highly reliable. RM resulted in significant decreases in soleus H-reflex amplitudes. High-intensity, moderate-intensity, and sham conditions decreased soleus H-reflex amplitudes by 58%, 43%, and 19%, respectively. H-reflexes induced with high-intensity rolling discomfort or pain were significantly lower than moderate and sham conditions. The effects were transient in nature, with an immediate return to baseline following RM. This is the first evidence of RM-induced modulation of spinal excitability. The intensity-dependent response observed indicates that rolling pressure or pain perception may play a role in modulation of the inhibition. Roller massage-induced neural modulation of spinal excitability may explain previously reported increases in ROM and PPT. NEW & NOTEWORTHY Recent evidence indicates that the benefits of foam rolling and roller massage are primarily accrued through neural mechanisms. The present study attempts to determine the neuromuscular response to roller massage interventions. We provide strong evidence of roller massage-induced neural modulation of spinal excitability to the soleus. It is plausible that reflex inhibition may explain subsequent increases in pain pressure threshold.

This is the first study to examine corticospinal excitability (CSE) to antagonistic muscle groups during arm cycling. Transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract were used to assess changes in supraspinal and spinal excitability, respectively. TMS induced motor evoked potentials (MEPs) and TMES induced cervicomedullary evoked potentials (CMEPs) were recorded from the biceps and triceps brachii at two positions, mid-elbow flexion and extension, while cycling at 5% and 15% of peak power output. While phase-dependent modulation of MEP and CMEP amplitudes occurred in the biceps brachii, there was no difference between flexion and extension for MEP amplitudes in the triceps brachii and CMEP amplitudes were higher during flexion than extension. Furthermore, MEP amplitudes in both biceps and triceps brachii increased with increased workload. CMEP amplitudes increased with higher workloads in the triceps brachii, but not biceps brachii, though the pattern of change in CMEPs was similar to MEPs. Differences between changes in CSE between the biceps and triceps brachii suggest that these antagonistic muscles may be under different neural control during arm cycling. Putative mechanisms are discussed.

Lockyer EJ, Benson RJ, Hynes AP, Alcock LR, Spence AJ, Button DC, Power KE. Intensity matters: effects of cadence and power output on corticospinal excitability during arm cycling are phase and muscle dependent. The present study investigated the effects of cadence and power output on corticospinal excitability to the biceps (BB) and triceps brachii (TB) during arm cycling. Supraspinal and spinal excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. Motor-evoked potentials (MEPs) elicited by TMS and cervicomedullary motor-evoked potentials (CMEPs) elicited by TMES were recorded at two positions during arm cycling corresponding to mid-elbow flexion and mid-elbow extension (i.e., 6 and 12 o'clock made relative to a clock face, respectively). Arm cycling was performed at combinations of two cadences (60 and 90 rpm) at three relative power outputs (20, 40, and 60% peak power output). At the 6 o'clock position, BB MEPs increased~11.5% as cadence increased and up to~57.2% as power output increased (P Ͻ 0.05). In the TB, MEPs increased~15.2% with cadence (P ϭ 0.013) but were not affected by power output, while CMEPs increased with cadence (~16.3%) and power output (up to~19.1%, P Ͻ 0.05). At the 12 o'clock position, BB MEPs increased~26.8% as cadence increased and up to~96.1% as power output increased (P Ͻ 0.05), while CMEPs decreased~29.7% with cadence (P ϭ 0.013) and did not change with power output (P ϭ 0.851). In contrast, TB MEPs were not different with cadence or power output, while CMEPs increased 12.8% with cadence and up to~23.1% with power output (P Ͻ 0.05). These data suggest that the "type" of intensity differentially modulates supraspinal and spinal excitability in a manner that is phase-and muscle dependent. NEW & NOTEWORTHYThere is currently little information available on how changes in locomotor intensity influence excitability within the corticospinal pathway. This study investigated the effects of arm cycling intensity (i.e., alterations in cadence and power output) on corticospinal excitability projecting to the biceps and triceps brachii during arm cycling. We demonstrate that corticospinal excitability is modulated differentially by cadence and power output and that these modulations are dependent on the phase and the muscle examined.

Spence, A-J, Helms, ER, and McGuigan, MR. Range of motion is not reduced in national-level New Zealand female powerlifters. J Strength Cond Res 35(10): 2737–2741, 2021—Some research suggests male powerlifters have less range of motion (ROM) in several directions about the shoulder and hip compared with sedentary men. In addition, those differences may be more pronounced in groups with higher strength levels and more years of experience. However, there is no information on ROM in female powerlifters. The purpose of this study was to evaluate single-joint ROM in competitive female powerlifters and determine whether single-joint ROM would be an effective predictor of strength in this population. Twelve female powerlifters and 12 female recreationally trained age-matched controls attended one testing session. Subjects reported their years of training experience, frequency, and average duration of training sessions. Active ROM measurements were collected at the shoulder, hip, and knee, using goniometry. There was no significant difference (p > 0.05) between groups for age, height, body mass, training experience, and training frequency. Powerlifters reported significantly greater (p ≤ 0.05) training durations than recreationally trained women. Powerlifters had significantly greater shoulder horizontal abduction on the right side (p = 0.022, g = 0.97), but no other ranges were significantly different between groups, and no ranges were significantly related to strength. Powerlifting does not seem to affect shoulder, hip, or knee ROM differently than recreational resistance training in women. Single-joint ROM was not an effective predictor of strength in female powerlifters.

Spence, A-J, Helms, ER, and McGuigan, MR. Stretching practices of International Powerlifting Federation unequipped powerlifters. J Strength Cond Res 36( 12): 3456-3461, 2022-Stretching practices in powerlifters. The purpose of this study was to provide insight into the stretching practices of competitive powerlifters. Powerlifters (n 5 319) from 51 countries completed a self-reported online survey on stretching practices. Subjects had (mean 6 SD, median, and interquartile range) 7.7 6 6.1, 6, and 6 years of general resisting training, 4.4 6 4.5, 3, and 3 years of strength specific training, and been competing in powerlifting for 3.0 6 3.7, 2, and 2 years with the average Wilks score being 366.4 6 52.2, 365, and 60. Analysis by sex and competitive standard was conducted. More than 50% (52.4%) of subjects (n 5 167) reported stretching; of those, 84.4% performed static stretches, and 90.4% performed dynamic stretches. Stretching was performed before resistance training by 77.8%, after resistance training by 43.7%, and 53.9% stretched independent of resistance training. Powerlifters who performed static stretches before training did an average of 6.72 6 10.31, 5, and 8 repetitions per stretch and held those stretches for an average of 30.8 6 31.4, 20, and 15 seconds; 90.1% also performed dynamic stretches. Powerlifters who performed static stretches after or independent of training did an average of 4.1 6 4.2, 2, and 9 repetitions per stretch and held those stretches for an average of 42.9 6 30.8, 30, and 33 seconds. The majority of powerlifters (66.9%) programmed stretching themselves, whereas only 10.2% had stretching programmed by their coach. These data will inform athletes and coaches about the prevalence and characteristics of current stretching practices in powerlifters.

No abstract

Spence, AJ, Helms, ER, Sousa, CA, and McGuigan, MR. Range of motion predicts performance in National-level New Zealand male powerlifters. J Strength Cond Res 37(1): 123–128, 2023—Previous research established that male powerlifters have less range of motion (ROM) in several movements about the shoulder and hip compared with sedentary male subjects. It is unclear if these differences in ROM are related to strength, training type, and years of training experience or if individuals with less ROM have a better propensity to gain strength. The purpose of this study was to compare strength and ROM in male powerlifters and recreationally strength-trained male subjects and to determine if ROM would be an effective predictor of strength in these groups. Twelve powerlifters and 12 recreationally strength-trained control subjects completed 1 repetition maximum (1RM) squat and bench press testing. In a subsequent session, active ROM was measured, and velocity data were collected during submaximal squat repetitions. There was no significant difference (p > 0.05) between the groups for age, height, body mass, training experience, and training frequency. Powerlifters had significantly greater (p ≤ 0.05) training duration and absolute squat and bench press 1RM. Powerlifters had significantly less shoulder extension and horizontal abduction, and hip flexion, extension, and adduction than recreationally strength-trained men. Significant negative relationships were found between 2-lift Wilks score (body mass relative strength) and shoulder extension and horizontal abduction, as well as hip flexion and extension. In powerlifters, significant negative relationships were found between competition Wilks score, shoulder extension, and hip flexion. Because these relationships correspond to the bottom position of the squat and bench press, it may be best to ensure that shoulder extension and hip flexion remain sufficient to achieve competition depth.

Background A goal of many who perform resistance training (RT) is to increase muscle mass and strength. An energy surplus is commonly advised to support such gains; however, if too large, it could cause unwanted fat gain without augmenting adaptation. Thus, we randomized 21 trained lifters into maintenance energy (MAIN), 5% (MOD), and 15% (HIGH) energy surplus groups while performing RT 3d/wk for eight weeks to determine if skinfold thicknesses (ST), squat and bench one-repetition maximum (1-RM), or biceps brachii or quadriceps muscle thicknesses (MT) were influenced by group assignment. COVID-19 complications reduced our ability to recruit and retain participants, leaving 17 completers. Thus, in addition to Bayesian ANCOVA group comparisons, we regressed outcomes against body mass (BM) changes to analyze the relationship between BM gain, ST increases, and increase in 1-RM and MT. For all outcomes we reported Bayes Factors (BF10) indicating the odds ratio of the likelihood of one hypothesis relative to another (e.g., a BF10 = 2 indicates the hypothesis is twice as likely as another) and coefficients of determination (R2) for regressions. Results ANCOVAs provided no evidence in support of the group model for MT or squat 1-RM. However, there was moderate (BF10 = 9.9) and strong evidence (BF10 = 14.5) that MOD increased bench 1-RM more than HIGH and MAIN, respectively. Further, there was moderate evidence (BF10 = 4.2) MOD increased ST more than MAIN and weak evidence (BF10 = 2.4) HIGH increased ST more than MAIN. The regression provided strong evidence that BM changes predicted changes in ST (BF10 = 14.3, R2 = 0.49) and weak evidence that BM changes predicted changes in biceps MT (BF10 = 1.4, R2 = 0.24), but no evidence any other variable was predicted by BM changes. Conclusions While some group-based differences were found, our larger N regression provides the most generalizable evidence. Therefore, we conclude faster rates of BM gain (and by proxy larger surpluses) primarily increase rates of ST gain rather than augmenting 1-RM or MT. However, the biceps, the muscle group which received the greatest stimulus in this study, may have been positively impacted by greater BM gain, albeit slightly. Our findings are limited to the confines of this study, where a group of lifters with mixed training experience performed moderate volumes 3d/wk for eight weeks. Thus, future work is needed to evaluate the relationship between BM gains, increases in ST and RT adaptations in other contexts.