Assessment of heart rate variability (HRV) is a common approach to examine cardiac autonomic nervous system modulation that has been employed in a variety of settings. Frequently, both the root mean square of successive differences (RMSSD) and SD1, which is a Poincaré plot component, have been used to quantify short-term heart rate variability. It is not typically appreciated, however, that RMSSD and SD1 are identical metrics of HRV. As a reminder to clinicians and researchers who use and study HRV, we show both empirically and mathematically that RMSSD and SD1 are identical metrics. Because the homology between RMSSD and SD1 is not commonly known, the inclusion of both measures has been reported in many recent publications. The inappropriate use of such redundant data may affect the interpretation of HRV studies. Muscle Nerve 56: 674-678, 2017.

• ▶ muscle-tendon stiff ness • ▶ infl ammatory response • ▶ injury • ▶ therapeutic modality Instrument-assisted Soft Tissue Mobilization: Eff ects on the Properties of Human Plantar Flexorstion following eccentric exercise may be important components for the recovery of muscle tissue [ 20 ] . Though this research provides the most recent mechanistic example of the response to soft tissue mobilization in an animal model, the physiological diff erences to that of human subjects may limit its clinical applicability [ 11 , 35 ] . In contrast, the research fi ndings on IASTM often describe clinical markers such as range of motion (ROM) and functional measures, but are not derived from randomized controlled studies [ 15 ] . Collectively, however, it appears that soft tissue mobilization therapies may play a role in reducing infl ammation [ 6 ] . The purpose of this project was to evaluate the eff ects of IASTM on intramuscular infl ammation, pain, ROM and strength following muscle damage in a randomized controlled laboratory experiment. Materials and Methods ▼ Subjects11 healthy men (mean ± SD age = 23 ± 3 years; stature = 181 ± 7 cm; mass = 83 ± 11 kg) volunteered for this investigation. Each participant was screened Introduction ▼ According to the marketing information for Graston Technique ® , a form of instrument-assisted soft tissue mobilization (IASTM), more than 16 000 clinicians currently employ this technique for treating soft tissue ailments [ 17 ] . This does not include the number of clinicians and alternative medicine providers utilizing other forms of IASTM techniques such as sound-assisted soft tissue mobilization (SASTM), ASTYM ® , GuaSha, or others. Interestingly, the ability of IASTM to ameliorate loss of function, pain and infl ammation has yet to be clarifi ed. There are several physiological hypotheses as to how soft tissue mobilization works. These include increased blood fl ow, increased lymphatic drainage of toxins, reduced tissue stiff ness, alteration in neuromuscular activity and a decreased infl ammatory response [ 48 ] . However, the current literature fails to support these claims. Recently, studies have evaluated the eff ects of soft tissue mobilization on the recovery of muscular attributes following eccentric exercise-induced muscle damage [ 13 , 14 ] . Interestingly, it has been demonstrated that the intensity of the compressive load and the timing of applica-

Our aim was to determine the effects of probiotic supplementation (Bifidobacterium longum 35624; 1 billion CFU·d−1) on exercise performance, immune modulation, and cognitive outlook in collegiate female athletes during six weeks of offseason training. Seventeen National Collegiate Athletic Association (NCAA) Division 1 collegiate female swimmers participated in this two-group matched, double-blind, placebo controlled design. Via stratified randomization, participants were assigned to probiotic (B. longum 35624; n = 8) or placebo (n = 9) groups. Pre, mid, and post-training, all participants completed exercise performance testing (aerobic/anaerobic swim time trials and force plate vertical jump) as well as provided serum (cytokine and gastrointestinal inflammatory markers) and salivary immunoglobulin A samples. Recovery-stress questionnaire for athletes (RESTQ-Sport) was administered at baseline and conclusion of each week. Data were analyzed by analysis of covariance (ANCOVA) by time point with the respective baseline values of each dependent variable being the covariate. No significant differences in exercise performance and biochemical markers were observed between groups following offseason training. Recovery-Stress Questionnaire for Athletes (RESTQ-sport) values in B. longum 35624 group had significantly higher (i.e., more desired; p < 0.05) values in sport recovery (weeks five and six) than placebo. Probiotic supplementation in collegiate female swimmers did not affect exercise performance or immune function throughout offseason training, but did indicate alterations in cognitive outlook.

Stimulation of the left insular cortex may affect heart rate variability (HRV) and exercise effort perception. These studies investigated the effects transcranial direct current stimulation (tDCS) and electrode orientation on HRV and repeated maximal knee extensions. In study 1, following sham stimulation, anodal left temporal lobe stimulation, or anodal right temporal lobe stimulation, 10 male and 10 female subjects (age=21.0±1.5 yr) completed 50 maximum isokinetic extensions at 180°s. There was a significant effect of stimulation condition on HRV for only one (SD2; p=.037; η=.159) of five HRV metrics. There was no significant effect on isokinetic fatigue percent, or isokinetic work (all p≥.278; all η≤.065). It has been proposed that placing the cathode electrode on the shoulder, may differentially affect tDCS. Therefore, in study 2, the effects of electrode orientation on tDCS-induced changes in HRV was assessed in ten healthy females and eight healthy males (21.6±2.5 yr) who completed cephalic, extracephalic, and sham trials. In the cephalic montage, the anode was placed over the left temporal lobe and the cathode was placed over right prefrontal cortex. In the extracephalic montage, the cathode was placed on the shoulder on the same side of the body as the anode. Neither cephalic nor extracephalic montages affected HRV (all p≥.152; all η≤.105). These data suggest that anodal tDCS of the insular cortex has little effect on HRV, and does not improve high-intensity exercise performance in the current population. Therefore, anodal tDCS applied over the left temporal lobe is not recommended for high intensity performance enhancement.

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