Phillip M. Gallagher

Relationships between skinfold thickness and electromyographic and mechanomyographic amplitude recorded during voluntary and non-voluntary muscle actions

INTRODUCTION The purpose of this study was to examine possible correlations between skinfold thicknesses and the a terms from the log-transformed electromyographic (EMGRMS) and mechanomyographic amplitude (MMGRMS)-force relationships, EMG M-Waves, and MMG gross lateral movements (GLM). METHODS Forty healthy subjects performed a 6-s isometric ramp contraction from 5% to 85% of their maximal voluntary contraction with EMG and MMG sensors placed on the vastus lateralis (VL) and rectus femoris (RF). A single electrical stimulus was applied to the femoral nerve to record the EMG M-waves and MMG GLMs. Skinfold thickness was assessed at the site of each electrode. Pearsons product correlation coefficients were calculated comparing skinfold thicknesses with the a terms from the log-transformed EMGRMS-and MMGRMS-force relationships, EMG M-waves, and MMG GLMs. RESULTS There were no significant cor1relations (p>0.05) between the a terms and skinfold thicknesses for the RF and VL from the EMGRMS and MMGRMS-force relationships. However, there were significant correlations (p<0.05) between skinfold thicknesses and the EMG M-waves and MMG GLMs for the RF (r=-0.521, -0.376) and VL (r=-0.479, -0.484). DISCUSSION Relationships were only present between skinfold thickness and the amplitudes of the EMG and MMG signals during the non-voluntary muscle actions.

Instrument-assisted soft tissue mobilization: Effects on the properties of human plantar flexors

The effect of instrument-assisted soft tissue mobilization (ISTM) on passive properties and inflammation in human skeletal muscle has not been evaluated. Passive properties of muscle, inflammatory myokines and subjective reporting of functional ability were used to identify the effects of ISTM on the plantar flexors. 11 healthy men were measured for passive musculotendinous stiffness (MTS), passive range of motion (PROM), passive resistive torque (PASTQ) and maximum voluntary contraction peak torque (MVCPT) for plantar flexor muscles of the lower leg. Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were measured from muscle biopsies from the gastrocnemius, and subjective measurements of functional ability were taken using the perception of functional ability questionnaire (PFAQ). MTS, PROM, PRT and MVCPT were measured in the treatment leg (TL) and control leg (CL) before, immediately after, 24 h, 48 h and 72 h following IASTM. Biopsies for IL-6 and TNF-α and PFAQ responses were collected before as well as 24 h, 48 h and 72 h after IASTM. There were no significant differences in MTS, PROM, PASTQ, MVCPT, IL-6 and TNF-α between the TL or CL. A significant decrease in the perception of function and a significant increase in pain for the TL were found following IASTM.

Intramuscular heating through fluidotherapy and heat shock protein response.

CONTEXT Therapeutic modalities that can increase intramuscular temperature commonly are used to treat injuries in the clinical setting. Researchers recently have suggested that the physiologic changes occurring during an increase in temperature also could provide a cytoprotective effect for exercise-induced muscle damage. OBJECTIVE(S) To determine if the Fluidotherapy treatment increases the inducible expression of heat shock protein (HSP), to identify the rate of heating that occurs in the lower extremity with Fluidotherapy treatment, and to evaluate the relationship between the inducible expression of HSP and temperature. DESIGN Controlled laboratory study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Six male (age = 21.67 ± 1.63 years, height = 180.09 ± 4.83 cm, mass = 87.60 ± 10.51 kg) and 6 female (age = 24.60 ± 4.59 years, height = 151.05 ± 35.76 cm, mass = 55.59 ± 14.58 kg) college-aged students. INTERVENTION(S) One lower extremity was randomly selected to receive the heat treatment, and the other extremity received no treatment. MAIN OUTCOME MEASURE(S) We measured intramuscular temperature every 10 minutes, determining peak intramuscular temperature by 2 identical sequential measurements, and we analyzed the time to peak temperature. We analyzed the amount of HSP70 expression and HSP27P:T (ratio of HSP27 to the total HSP27 expression) in the gastrocnemius and soleus muscles and measured baseline skinfold thickness and estradiol levels. RESULTS Fluidotherapy increased intramuscular temperature by 5.66 ± 0.78°C (t11 = 25.67, P < .001) compared with baseline temperature, with a peak temperature of 39.08°C ± 0.39°C occurring at 84.17 ± 6.69 minutes. We did not find a heat treatment effect for HSP70 or HSP27P:T in the gastrocnemius or soleus muscles (P > .05). Peak temperature and the percentage change of HSP70 were positively correlated for the gastrocnemius and soleus muscles (P < .05). We found no other correlations for skinfold thickness, sex, or estradiol levels (P > .05). No effect of sex for skinfold thickness or estradiol levels at baseline was discovered (P > .05). CONCLUSIONS This Fluidotherapy protocol increased the intramuscular temperature to a therapeutic level; however, it did not stimulate inducible HSP70 or HSP27P:T in the soleus and gastrocnemius muscles regardless of sex or skinfold thickness. These data confirmed that Fluidotherapy is an effective heating modality but suggested it is not an effective method for stimulating an HSP response in the lower limb.

Methodological Differences in the Interpretation of Fatigue Data from Repeated Maximal Effort Knee Extensions

Background : Isokinetic fatigue protocols are commonly used in both research as well as in kinesiology education. However, fatigue quantification methods vary between studies. Objective : Therefore, the purpose of this study was to determine how fatigue quantification methods affect data interpretation and which methods may be most appropriate. Method : In this study, we quantified fatigue from a repeated maximal effort isokinetic knee extension test using different methods, as seen in published research. Nine healthy males and nine healthy females performed 50 concentric knee extensions at 180°•s-1. For each repetition, torque was quantified as either peak torque (PT), torque at the mid-point of the range of motion, and torque integrated over the full, middle 30° range of motion, and isokinetic range of motion. Fatigue Index was quantified using either the first and last three or five repetitions or the peak and last three or five repetitions. Torque slopes were quantified using all repetitions or repetitions that occurred at and beyond the repetition at which the greatest torque value occurred. Results : There was a significant inverse relationship between angle at PT and repetition number. Measures of fatigue were overestimated when torque integral over the isokinetic range of motion was utilized. When the first three or first five repetitions were utilized for Fatigue Index calculations, fatigue was underestimated. Conclusion : Results suggest that torque integral over the full range of motion is likely the best representation of strength or work. Also, researchers should omit the first few repetitions from their quantification of Fatigue Index or torque slope.

Acute Endocrine Responses to Maximal Velocity Barbell Squats with Three Different Loads

Many strength and conditioning programs incorporate high power speed squats as part of the training regimen. The training specificity principle suggests that high power speed squats contribute to high power performance during sports performance, most likely due to the recruitment strategies required. What are not clear are the acute endocrine responses that result from this type of exercise. PURPOSE: To determine the acute endocrine responses to maximal velocity barbell squats at three different external loads. METHODS: Seven healthy recreationally weight trained men (X 6 SE; age = 21.4 6 0.6 yrs, hgt. = 1.83 6 0.02 m, wgt. = 92.0 6 3.7 kg, squat 1 RM = 152.7 6 13.4 kg) completed each of three speed squat protocols in randomized order on nonconsecutive days. The three lifting protocols were as follows; 5 3 3 at 90% 1 RM (heavy), 5 3 5 at 70% 1 RM (medium) and 5 3 10 at 30% 1 RM (light). Blood samples obtained from an antecubital vein pre-exercise (Pre) and 5 min. post-exercise (Post) were analyzed for lactate (HLa), total testosterone (Tes), cortisol (Cort) and immunoreactive growth hormone (GH). Data were analyzed using 2 x 3 (time 3 load) or 1 3 3 (3 loads) repeated measures ANOVAs (*p,0.05 vs. pre, †p,0.05 vs. light load). Data are reported as X 6 SE. RESULTS: Mean power for all repetitions at each load were; heavy = 1,071.7 6 57.6 W, medium = 1,244.2 6