The Effect of Various Body Positions on Performance of the Isometric Mid-Thigh Pull

The purpose of this dissertation was to evaluate the effects of changing body position on the execution of the isometric mid-thigh pull (IMTP). Furthermore, while there is evidence to suggest that there is an effect of familiarization on performance of maximal strength tests, there has been no known research evaluating the effect of learning on the IMTP. The effect of familiarization was assessed by evaluating changes in variables obtained from the IMTP. Subjects did not statistically improve over the five IMTP testing sessions, regardless of the body position used, or if subjects had previous experience with weightlifting derivatives. This may indicate that little familiarization is needed for subjects to perform the IMTP before acute increases due to learning stabilize. When body positions were compared, there were differences in force production whether subjects had or did not have experience with weightlifting movements. The magnitude of difference between body position was affected by weightlifting movement experience; lifters with \u3e6 months experience with weightlifting had larger differences in force production between position. Average muscle activation for a variety of muscles, evaluated with surface EMG, appeared to differ between body positions, although these positions are idiosyncratic to experience level. In particular, lumbar erector spinae activation was higher in the bent position for both groups, which may have implications for low back injury risk.In entirety, it appears that if maximizing force production is the goal, the upright positon is optimal. Furthermore, the differing body positions have meaningfully different effects on how 3 much individual muscles are activated between positions. Lastly, substantial familiarization does not appear to be necessary before subjects perform the IMTP

Isometric Mid-Thigh Pull Performance in Rugby Players: A Systematic Literature Review

The isometric mid-thigh pull (IMTP) is a multi-joint test of whole-body force production relevant to rugby players. “Rugby AND (mid-thigh pull OR midthigh pull OR mid thigh pull” were searched in PubMed, Sportdiscus, Academic Search Premier, CINAHL Plus with Full Text, and Google Scholar; the final date of search was 24 January 2018. Data extraction from 24 articles included subject characteristics, force data, and IMTP testing procedures. Select ranges of peak forces reported were: Youth: 1162–2374 N; Academy: 1855–3104 N; Professional: 2254–3851 N. Rate of force development (RFD) at 100 and 200 ms ranged from 5521 to 11,892 N and 5403 to 8405 N, respectively, among professional rugby players. Studies’ research design were of moderate quality, but most studies lacked detailed reporting of IMTP procedures. Variability of force characteristics derived from the IMTP within similar populations (e.g., approximately 200% difference in peak force between samples of professional rugby league players) as well as large and unexpected overlaps between dissimilar populations, limit conclusions about force production capabilities relative to playing level, likely due to limitations and lack of standardization of IMTP procedures. Greater uniformity in IMTP testing procedures and reporting is needed. This manuscript provides a guide for reporting needs when presenting results from an IMTP in research

GOLF BIOMECHANICS: IMPLICATIONS FOR PERFORMANCE AND THE LUMBAR SPINE

Golf is one of the most popular sports in the world today. It offers accessibility to a wide range of ages, physical abilities, and levels of expertise. Novices and experts alike desire maximal performance with the game of golf, and often encounter musculoskeletal injuries in their quest to perform at the highest level possible. The most common injury associated with golf is low back pain. The purpose of this paper is to review the physical conditioning approaches to minimize the incidence and severity of low back pain while maximizing golf performance, present information related to normal lumbar spine mechanics, and discuss the stress imposed upon the lumbar spine from the game of golf

Calibration and Multiple Reliability Assessments of a Scrum Machine Instrumented to Measure Force

Coaches need reliable methods of quantifying rugby union scrum force performance in order to make data-driven decisions. The purpose of this study is to present the reliability of a replicable instrumented scrum machine. We performed 3 phases of deadweight calibration on 8 S-type load cells; during deadweight calibration, each load cell was loaded with ~20–200 kg. Phase 1 compared power sources (wall outlet vs. portable power station). Phase 2 tested the inter-session reliability of the load cells after 15, 30, 45, 60, and 420 min of run time. Phase 3 tested between-session reliability, comparing days 0, 1, 7, and 180. We also performed a phase of inter-trial reliability when humans pushed on the fully instrumented scrum machine. Fourteen collegiate rugby players performed four warm-up trials and then five 100%-effort trials; peak and average voltage during the push were compared between the 100%-effort trials. For all phases, statistical analyses show near-perfect reliability. Therefore, we conclude that our novel instrumented scrum machine is ready for in vivo data collection; other coaches or researchers could duplicate our methods to create their own reliable instrumented scrum machine

Changes in University Club Athletes’ and Non-Athlete Students’ Stress and Perceived Gains Across a Semester

To examine the relationship between club rugby participation, collegiate experiences, and perceived gains, 25 rugby players and 25 non-athlete students completed the Student-Athlete Experiences Inventory-Revised, Student-Athlete Gains Inventory, and Perceived Stress Scale at the start and end of a semester. A RM-ANOVA and partial-η2 effect sizes determined if group and time differences were present. We selected variables associated with the post-scores for practical and liberal arts gains with the lasso method. Rugby players engaged in more diverse social interactions (partial-η2 = 0.091) and were more actively involved on campus (partial-η2 = 0.0914) than non-athlete students, but paradoxically had lower practical arts gains (p \u3c 0.0001). All students reported increasing stress levels from start to end of the semester (partial-η2 = 0.109), which contributed to decreasing practical arts gains. Students need help with stress management near semester’s end. Club rugby players should seek support services on campus to improve career preparedness

Identifying a Test to Monitor Weightlifting Performance in Competitive Male and Female Weightlifters

Monitoring tests are commonly used to assess weightlifter’s preparedness for competition. Although various monitoring tests have been used, it is not clear which test is the strongest indicator of weightlifting performance. Therefore, the purpose of this study was to (1) determine the relationships between vertical jump, isometric mid-thigh pull (IMTP) and weightlifting performance; and (2) compare vertical jumps to IMTP as monitoring tests of weightlifting performance in a large cohort of male and female weightlifters. Methods: Fifty-two competitive weightlifters (31 males, 21 females) participated in squat and countermovement jump testing (SJ, CMJ), and IMTP testing performed on force plates. All laboratory testing data was correlated to a recent competition where the athletes had attempted to peak. Results: Squat jump height (SJH) was the strongest correlate for men and women with the Sinclair Total (r = 0.686, p ≤ 0.01; r = 0.487, p ≤ 0.05, respectively) compared to countermovement jump height (r = 0.642, p ≤ 0.01; r = 0.413, p = 0.063), IMTP peak force allometrically scaled to body mass (r = 0.542, p ≤ 0.01; r = −0.044, p = 0.851) and rate of force development at 200 ms (r = 0.066, p = 0.723; r = 0.086, p = 0.711), respectively. Further, SJH was a stronger correlate of relative weightlifting performance compared to IMTP peak force in females (p = 0.042), but not male weightlifters (p = 0.191). Conclusions: Although CMJ and IMTP are still considered strong indicators of weightlifting performance, SJH appears to be the most indicative measure of weightlifting performance across a wide-range of performance levels. Thus, SJH can be used as a reliable measure to monitor weightlifting performance in male and female weightlifters

Changes in Peak Acceleration in the Snatch Across Multiple - Attempts in Training: A Case Study

Accelerometers are devices that have been recently used to assess the performance of weightlifters in training. This case study used vertical acceleration data to assess multiple snatch attempts in a single lifter during a training session. The lifter exhibited variability in a number of measures, including peak acceleration and peak velocity. The measures calculated from the acceleration-time data did not show consistent trends between made and missed lifts. More work is needed identify variables of interest for snatch performance

CHANGES IN PEAK ACCELERATION IN THE SNATCH ACROSS MULTIPLE ATTEMPTS IN TRAINING: A CASE STUDY

Accelerometers are devices that have been recently used to assess the performance of weightlifters in training. This case study used vertical acceleration data to assess multiple snatch attempts in a single lifter during a training session. The lifter exhibited variability in a number of measures, including peak acceleration and peak velocity. The measures calculated from the acceleration-time data did not show consistent trends between made and missed lifts. More work is needed identify variables of interest for snatch performance

Reliability and Criterion Validity of the Assess2Perform Bar Sensei

The Assess2Perform Bar Sensei is a device used to measure barbell velocity for velocity-based training that has not yet been validated. The purpose of this study was to determine criterion validity and reliability of the Assess2Perform Bar Sensei in barbell back squats by comparing it against the GymAware PowerTool, a previously validated instrument. Sixteen injury-free, resistance-trained subjects (eleven males and five females) were recruited. Subjects were tested for their back squat one repetition maximum (1RM). Then, on two separate days, subjects performed two sets of three repetitions at loads of 45%, 60% and 75% 1RM. The GymAware PowerTool and Bar Sensei were attached to the barbell in similar locations for concurrent collection of mean concentric velocity (MCV) and peak concentric velocity (PCV). The Bar Sensei and PowerTool showed generally fair to poor agreement for MCV and PCV when subjects lifted 45% of 1RM (intraclass correlation;ICC 0.4–0.59), and they showed poor agreement when subjects lifted 60% and 75% of 1RM (ICC 0.3–0.4). Inter-repetition/within-set reliability for the Bar Sensei ranged between ICC = 0.273–0.451 for MCV and PCV compared to the far more reliable PowerTool (ICC = 0.651–0.793). Currently, the Bar Sensei is not a reliable or valid tool for measuring barbell velocity in back squats

REACTIVE STRENGTH INDEX-MODIFIED: A COMPARISON BETWEEN SIX U.S. COLLEGIATE ATHLETIC TEAMS

The purpose of this study was to compare reactive strength index-modified (RSImod) between six U.S. collegiate sport teams. One hundred six athletes performed maximum effort countermovement jumps during unloaded and loaded conditions. RSImod measures for each team were compared using one-way ANOVAs, and Bonferroni post hoc tests where warranted. Statistically significant differences in RSImod values existed between teams during both unloaded (< 1kg) and loaded (20kg) conditions. The greatest RSImod values during both conditions were produced by men’s soccer and followed in order by baseball, women’s volleyball, men’s tennis, women’s soccer, and women’s tennis. The data indicate that athletes from different sports possess different reactive strength characteristics