Positional Differences in Running Distance and Speed Among Collegiate Rugby 7s Players

Rugby sevens (7s) is an anaerobic contact sport consisting of seven players per team, with two 7-minute halves per match played in tournament style with several matches over up to a three-day event. However, due to the nature of the collegiate game, less funding, and their academic schedule, the tournaments are commonly consolidated into one day (minimum 3, as many as 6 matches). While there are six positions in 7s, this study divided them into three groups: Forwards (FW), Backs (BK), and Scrum halves (SH). Purpose: The purpose of this investigation was to identify the physiological and physical demands between positions of Indiana University 7s club players. Methods: Data was retrospectively analyzed from male (n = 15) collegiate rugby 7s players. Data was collected at Indiana University using GameTraka (Sports Performance Tracking, Victoria, Australia) and data represented here are from one tournament consisting of 5 matches on the same day. Participants wore Global Positioning System (GPS) units from which information on distances run per minute by each position group (FW, BK, and SH) was measured within six different speed zones. A one-way ANOVA was used to determine between group differences by each half of play with Tukey post-hoc analyses to reveal differences between positions. A two-way repeated measures ANOVA was used to determine if differences existed across matches by player position. A p-value of \u3c0.05 was set to determine the level of statistical significance. Results: During the first half no significant differences were seen. In the second half of match #1, significant differences were found in Zone 1 running (p = 0.004) indicating that BK ran more than both FW (p = 0.003) and SH (p = 0.05). No significant differences were found in the second half of matches 2-4. Match #5 second half results indicated significant difference in distance per minute (p = 0.022) with both FW (p = 0.036) and SH (p = 0.041) covering more distance than BK. A main effect for zone 1 (p = 0.015) and zone 4 (p = 0.003) were observed with both FW (p = 0.029) and SH (p = 0.003) higher than BK. No significant differences were found across the five matches between position groups. GPS data indicate that the primary differences between position groups are observed in the second halves of rugby 7s matches. Data suggests that FW and SH have a higher distance covered per minute and spend more time in the different running zones as the number of matches increases. This could be a byproduct of a change in the quality of play as peripheral fatigue sets in as the match progresses. Conclusion: Data presented here can affect the training approaches for the various position groups as the data suggests a greater amount of physiological exertion is present in the later matches of tournament play. Data also may be useful to coaches in the strategic utilization of substituting players as substitutions per match are capped in rugby 7s

Differences in Impact and Load During Collegiate Rugby 7s

Rugby 7s is a sport played with seven players, and two, 7-minute halves, played on a standard rugby field of 100 meters long by 70 meters wide. Impacts with forces greater than 10.0 Gs are an often occurrence in rugby 7s, and the occurrence can be quite frequent in such a short period of time (14 minutes of match play). Multiple matches are played in a day or throughout a weekend in tournament format thus adding to the load on players and current research on the amount of impact and load players experience is lacking in a U.S. collegiate population. Purpose: The purpose of this investigation was to assess differences in impact and load during collegiate rugby 7s matches. Methods: Data was collected at Indiana University from male collegiate rugby 7s players (n = 15) by their head coach using GameTraka (Sports Performance Tracking, Victoria, Australia) during their 2019 season. Participants wore GPS units that collected data on impact and load by position groups forwards (FW), backs (BK), and scrum halves (SH). A one-way ANOVA was used to determine between group differences by each half of play with Tukey post-hoc analyses to reveal differences between positions. A two-way repeated measures ANOVA was used to determine if differences existed across matches by player position. A p-value of \u3c0.05 was set to determine the level of statistical significance. Results: Data analyses revealed a significant difference in number of impacts during the first half of match 1 (p = 0.014). Post-hoc analyses indicated FW incurred a significantly higher number of impacts than BK (p = 0.046), as well as more impacts than SH (p = 0.012). During the second half of play, the only match with a significant difference was match 5. Both summation of horizontal forces (loading 2D) as well as summation of horizontal and vertical forces (loading 3D) to the athlete revealed significant main effects. For the loading 2D and loading 3D during match 5, post-hoc analyses revealed significant differences between BK and SH at p = 0.048 and p = 0.045, respectively. In comparison of position across matches, no significant differences were found for impacts, 2D, or 3D loading. No significant differences were found across the five matches. Conclusion: This data suggests that the number of impacts is higher in the first half, with FW having significantly more impacts when compared to BK and SH. This is likely explained by task differences between FW, BK, and SH as FW are required to compete in scrums and more rucks than either BK or SH and tend to encounter contact more frequently. Differences in the second half occurred only in match 5 with SH being subjected to more forces than BK. This effect is likely a result of the positional differences as SH follow the course of play much more so than BK. This data supports that FW incur the greatest amount of collisions in rugby 7s compared to other positions also being a byproduct of the role that FW play in rugby 7s. There was no significant difference in loading and impact across matches

Comparison of Bioimpedance Analysis and Dual Energy X-Ray Absorptiometry in Division III Football Athletes

Body composition is an integral component of physiology and pathology, as well as an indication of how the musculoskeletal system changes over time in response to training and/or nutritional modifications. Two common methods of estimating body composition include bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). There is a debate regarding the agreement between these two methods, and it is thought that the population being tested may influence the similarity of estimates obtained by these technologies. Limited data comparing these two methodologies in athletic populations are available. PURPOSE: The purpose of this study was to take examine the agreement between BIA and DXA for estimates of body mass (BM) and body fat percentage (BF%). METHODS: Forty-three division III football players (mean ± SD; age: 19.9 ± 1.7 y; height: 179.7 ± 7.4 cm; BM: 100.3 ± 21.9 kg; DXA BF%: 21.8 ± 7.1%) reported to the Human Performance Lab after abstaining from exercise for the previous 24 hours and fasting from food/beverages (except water) for 12 hours. After an initial height assessment, BM and BF% were assessed using both BIA (Inbody 770) and DXA (Hologic Horizon W). BIA was performed in the standing position using an 8-point electrode arrangement. The electrode panels were placed at the hands and feet. DXA was performed with the participants in a supine position and hips internally rotated. Differences in BM and BF% from DXA and BIA were compared using paired-samples t-tests, Bland-Altman analysis, and validity metrics. RESULTS: BM detected by DXA was significantly lower than BM obtained from the BIA scale (DXA: 98.2 ± 20.8 kg, BIA: 100.3 ± 21.9 kg; p \u3c 0.001). Additionally, Bland-Altman analysis indicated significantly greater underestimation of BM by DXA in individuals with higher BM values (slope: 0.053; p \u3c 0.001). BF% did not significantly differ between DXA and BIA (DXA: 21.8 ± 7.1%, BIA: 21.8 ± 8.4%; p = 0.86). However, Bland-Altman analysis indicated significant proportional bias, with underestimations of BF% by BIA in leaner individuals but overestimations of BF% in those with higher BF% (slope: 0.176; p = 0.005). The total error and 95% limits of agreement for BF% were 3.2% and ± 6.4%, respectively. CONCLUSION: This study demonstrates that although DXA and BIA exhibit good group-level agreement for BF%, several inconsistencies between these methodologies are present. Estimates of BM differed between technologies. Additionally, proportional bias for BF% was observed indicating different levels of agreement between DXA and BIA depending on the body fat of the individuals being tested. Based on these findings, caution should be employed when interpreting data from DXA and BIA assessments in athletic populations

Associations of Changes in Body Composition and Athletic Performance in Collegiate American Football Players

Football practitioners ubiquitously employ offseason resistance training to improve on-field performance. Early offseason training is frequently designed to emphasize accretion of lean and total body mass. While this is a main objective of sport-specific conditioning, there are few investigations comparing correlated changes in body composition, maximal strength, and football-specific performance tests after an early-offseason training program. PURPOSE: The purpose of this analysis was to quantify the relationship between changes in athletic performance and body composition in collegiate American football players. METHODS: Before and after a 7-week offseason training program, body composition and athletic performance were assessed in NCAA Division III American football players. Body composition was estimated using dual-energy X-ray absorptiometry (DXA; Hologic Horizon). One-repetition maximum (1RM) strength was assessed for the barbell back squat and front squat exercises. Vertical jump height, 40-yard dash time, broad jump distance, and pro agility shuffle time were also assessed. The sample size ranged from 17 to 19, depending on the specific performance test. Using Pearson’s product-moment correlations, the relationships between percent changes in DXA variables and athletic performance outcomes were examined.RESULTS: A trend for a positive correlation between changes in lower body FFM and front squat 1RM (r: 0.43, p: 0.08), but not back squat 1RM (r: -0.03, p: 0.92), was observed. Additionally, a significant positive correlation was observed between pro agility shuffle time and DXA BM (r: 0.50, p: 0.03) and total FFM (r: 0.49, p: 0.04), but not FM (r: 0.06, p: 0.80). In contrast, no correlations between changes in body composition variables and changes in vertical jump height, 40-yard dash time, or broad jump height were observed (range of r: -0.36 to 0.31, p\u3e0.05 for all).CONCLUSION: Increases in FFM may predict improvements in front squat 1RM but impairments in pro agility shuffle performance, with no relationships observed for vertical jump height, 40-yard dash time or back squat. Additional phases of training that specialize in developing maximal power and velocity are likely necessary to maximize athletic development

Offseason Body Composition Changes Detected by Dual-Energy X-Ray Absorptiometry Versus Multifrequency Bioelectrical Impedance Analysis in Collegiate American Football Athletes

In American football, offseason training is designed to promote increases in muscle strength and size in athletes. Tracking changes in body composition may confer key information about the effectiveness of training programs to football practitioners. PURPOSE: The present study assessed the relationship between body composition changes estimated by dual-energy x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) in football players during the initial period of an offseason training program. METHODS: Body composition in 29 NCAA Division III American football players (mean ± SD; age: 19.7 ± 1.5 y; height: 179.8 ± 6.6 cm; body mass [BM]: 96.1 ± 12.6 kg; DXA body fat: 20.9 ± 4.4%) was estimated using BIA (InBody 770) and DXA (Hologic Horizon) before and after a seven-week training intervention. Repeated measures analysis of variance, concordance correlation coefficients, and Bland-Altman analysis alongside linear regression were used to detect differences in cross-sectional estimates and change values, the strength of correlation, and determine the degree of proportional bias between methods, respectively. RESULTS: Significant method by time interactions were observed for BM (p = 0.03), arms fat-free mass (FFM) (p = 0.03), and legs FFM (p = 0.01). Post hoc comparisons indicated that DXA – but not BIA – detected increases in FFM of the arms and legs. Time main effects indicated an increase in total FFM (p = 0.004) and trunk FFM (p = 0.002) from pre to post. Finally, method main effects indicated higher leg FM values for DXA (p \u3c 0.001) and higher trunk FM values for BIA (p \u3c 0.001). No significant effects were observed for total FM (p = 0.92) or arms FM (p = 0.13). Changes in total BM (CCC = 0.96), FFM (CCC = 0.49), and fat mass (CCC = 0.50) were significantly correlated between BIA and DXA. CONCLUSION: DXA and BIA may similarly track increases in whole-body FFM in American collegiate football players; however, BIA may possess less sensitivity to detect segmental FFM increases, particularly in the appendages

Performance and Body Composition Changes Following an Offseason Training Period in DIII Collegiate American Football Athletes

Current literature shows that body composition and increased muscle mass correlate with improved performance for American football players thus assessment of these variables at appropriate times throughout competitive cycle are important for tracking individual adaptions but also in assessing the effectiveness of the prescribed training program. PURPOSE: This study assessed changes in anaerobic performance, total body mass (BM), fat-free mass (FFM), and percent body fat (PBF) in football players following a seven-week offseason mesocycle. METHODS: 29 NCAA Division III football players (mean ± SD; age: 19.7 ± 1.5 y; height: 179.8 ± 6.6 cm; body mass [BM]: 96.1 ± 12.6 kg; DXA body fat: 20.9 ± 4.4%) participated in assessments of performance and body composition body pre- and post- mesocycle. Performance testing was assessed at pre- and post-training timepoints on a subset of athletes that were not restricted (injury, etc.) from maximal testing at these timepoints. This data was from the initial cycle of their offseason training program which included seven weeks of hypertrophy focused training volumes. Performance tests administered included: bench press 1 RM (BP), bench press reps (BPR), incline bench press, back squat 1RM (BS), front squat 1 RM (FS), hang clean 3 RM, 40-yard dash (YD), broad jump, vertical jump (VJ), and pro agility shuttle. BM, FFM, and PBF were estimated via dual x-ray absorptiometry (DXA). RESULTS: Performance improved in all tests except for broad jump and pro agility shuttle. Post-mesocycle performance increases were observed in BP (p \u3c 0.001), BPR (p \u3c0.001), BS (p \u3c0.001), FS (p \u3c 0.001), YD (p \u3c 0.001), and VJ (p \u3c 0.001). Significant training induced changes were observed for: BM increased 1.12kg (p \u3c 0.01962), PBF decreased by 0.686 kg (p \u3c0.004), and FFM increased by 1.57 kg (p \u3c 0.0001). CONCLUSION: This study confirms that a well-structured strength and conditioning program for Division III football players will improve performance in a variety of strength and power related assessments. These changes, though observed over a relatively short amount of time, can translate to competitive performance in conjunction with improved body composition and fat-free mass increases

Lower Limb Muscle Activation and Recruitment Patterns Measured via Electromyography in Back Squat Variations

The squat is a fundamental exercise performed by athletes to improve muscular fitness. There are many variations of the back squat including the chained squat, box squat, and barefoot squat. Strength training literature recommends the inclusion of proper squats for athletes as well as variations of the squat to improve adaptations. Several studies have been published that analyze the neuromuscular relationship using electromyography (EMG) but few studies exist that compare EMG responses between squat variation. Purpose: Thus, the purpose of this investigation was to compare the electromyography (EMG) amplitude of the gluteus maximus (GM), biceps femoris (BF), and vastus lateralis (VL) during a back, chained, barefoot, and box squat. Methods: Seven college-aged resistance trained volunteers, three men and four women (age 21.4 ± 0.98; height 166.87 ± 12.84cm; weight 77.44 ± 18.52kg; percent body fat 22.97 ± 9.51 BF%) were recruited for this study and completed a baseline testing session to determine 70% of their 1 repetition maximum (1RM) and familiarize subjects with the squat variations: box, barefoot, back, and chained squats. Following the first testing session, each subsequent session occurred after a one-week washout period. EMG testing sites were located at each session via anatomical landmarks and palpation then abraded prior to applying surface electrodes in a bipolar configuration. Using the BIOPAC MP3X and Biopac system software, EMG activity was recorded through an integrated, high pass frequency filter. Participants performed 5 sets of 10 repetitions for each randomly assigned squat variation and data was analyzed for peak and mean values from the 1st set. Frequencies were normalized and recorded in millivolts (mV). The values from the subjects’ dominant leg were then analyzed using a one-way ANOVA with a p-value of \u3c0.05 was set to determine the level of statistical significance. Results: No significant differences were observed between back squat variations for both peak (VL: p = 0.817; BF: p = 0.941; GM: p = 0.766) and mean (VL: p = 0.877; BF: p = 0.738; GM: p = 0.602) EMG values. VL mean activation values (mean±SD) were as followed for the squat variations: back 0.254 ± 0.164, barefoot 0.297 ± 0.179, box 0.337 ± 0.239, chained 0.294 ± 0.155. VL peak activation values (mean±SD) were as followed for the squat variations: back 0.522 ± 0.335, barefoot 0.652 ± 0.395, box 0.720 ± 0.486, chained 0.650 ± 0.320. Conclusions: Despite varying levels of VL peak activation, this data suggests EMG activity for each muscle group does not seem to vary significantly between the squat variations used in this study. Data was collected from each leg which could be used in a future study to identify imbalances when compared to leg dominance across squat variation. The results could be applied clinically and practically in that multiple back squat variations can elicit similar muscular activation levels in a resistance-trained population

Relationship Between Changes in Upper Body Fat-Free Mass and Bench Press Performance in American Football Players

Horizontal pushing strength and strength endurance are relevant attributes for blocking and block shedding in American football. Since most positions in American football require the ability to either block or shed a block, and since bench press repetitions to failure (RTF) with 225 pounds is a component of the NFL draft combine, improving horizontal pushing strength and strength endurance have been key areas of emphasis for strength and conditioning coaches working with these athletes. PURPOSE: The purpose of this analysis was to quantify the relationship between changes in upper body fat-free mass (FFM) and metrics of bench press performance in American football players. METHODS: Body composition and muscular performance were assessed in NCAA Division III American football players. Upper body FFM was obtained from dual-energy X-ray absorptiometry (DXA; Hologic Horizon) before and after a seven-week offseason training period. Barbell bench press one-repetition maximum (1RM), incline barbell bench press 1RM, and RTF with 225 pounds on the barbell bench press were also determined before and after the training period. Using Spearman’s rank correlations, the relationships between percent changes in upper body FFM and bench press 1RM (n=19), bench press RTF with 225 pounds (n=15), and incline bench press 1RM (n=18) were evaluated. RESULTS: Relative changes in bench press 1RM and DXA upper body FFM exhibited a weak, non-significant correlation (ρ: 0.38, p: 0.11). However, there was a moderate strength, significant correlation between relative changes in bench press RTF with 225 pounds and DXA upper body FFM (ρ: 0.53, p: 0.04). For relative changes in incline bench press 1RM, there was a weak, non-significant correlation with DXA upper body FFM (ρ: 0.24, p: 0.36). CONCLUSION: Of the performance tests assessed, only changes in bench press RTF with 225 pounds and changes in DXA upper body FFM were positively correlated. Therefore, strength and conditioning coaches working with athletes who plan on entering the NFL draft may want to consider dedicating time to increasing upper body FFM gains prior to the draft as it appears to be positively correlated with performance on this NFL combine test

The Effects of a Thermogenic Supplement on Metabolic and Hemodynamic Variables and Subjective Mood States

Thermogenic supplements are widely used in the general population to support attempted fat loss; however, the efficacy and safety of these supplements are questioned. PURPOSE: To determine whether a thermogenic supplement affects metabolic rate, hemodynamic responses, and mood states. METHODS: In a randomized double-blind crossover design, 23 females (22.2 ± 3.5 y; 164.8 ± 6.4 cm; 73.5 ± 6.9 kg) who were moderate caffeine consumers (\u3c150mg/day) reported to the lab on a 12-hour fast for baseline assessments of resting energy expenditure (REE) via indirect calorimetry, heart rate (HR), blood pressure (SBP and DBP), and hunger, satiety, and mood states. Thereafter, subjects ingested the assigned treatment (active treatment containing caffeine, micronutrients, and phytochemicals [TR] or placebo [PL]). All variables were reassessed at 30-, 60-, 120-, and 180-minutes post-ingestion. Subjects repeated the same protocol with ingestion of the opposite treatment on a separate day. All data were analyzed using a 2x5 ANOVA with repeated measures and significance was accepted a priori at p\u3c0.05. RESULTS: In the TR group, mean increases in REE of 121 to 166 kcal/d were observed at 30-, 60-, and 180-minutes post-ingestion (p\u3c0.01 for all). PL group mean decreases in REE of 72 to 91 kcal/d were observed at 60-, 120-, and 180-minutes (p\u3c0.05 for all). Similarly, TR resulted in mean increases in expired carbon dioxide of 13 to 19 mL/min at 30- and 60-minutes (p\u3c0.05 for both), and oxygen consumption increased by 12 to 24 mL/min at 30-, 60-, 120-, and 180-minutes (p\u3c0.05 for all) post-ingestion. Respiratory quotient decreased at 120- and 180-minutes in both treatments. A mean decrease in HR of 5 bpm was observed at 30-minutes post-ingestion of TR (p\u3c0.01). Slight increases in SBP of 3 to 4 mmHg were observed at 30-, 120-, and 180-minutes (p\u3c0.05 for all) post-ingestion of TR, while no effects were observed for DBP. Observed increases in SBP were within normal blood pressure ranges. TR decreased subjective fatigue with no other significant changes in mood states. CONCLUSION: These findings indicate that ingestion of a specific thermogenic supplement formulation produces a sustained increase in metabolic rate and caloric expenditure and reduces fatigue over three hours without producing adverse hemodynamic responses

Within Game and Between Gender Comparisons of Match Demands in Men’s and Women’s International Touch Rugby World Cup

Touch rugby is an intermittent, high-intensity, anaerobic team sport that is widely played internationally as the Federation of International Touch includes 47-member nations. PURPOSE: The present study quantified and compared the match demands of men’s and women’s international touch rugby players during the 2019 world cup. METHODS: Match demands (male: n=16; female: n=15) were assessed via 5Hz global positioning system devices. Separate linear mixed models and Cohen’s effect size comparisons were used to compare variables within matches (1st v 2nd half) for men’s and women’s only matches, while between gender comparisons were made for complete match demands. RESULTS: Within match comparisons revealed significant, small reductions in running distance (p = 0.003) and one-minute peak average speed (p = 0.019) for men’s matches in the second half compared to the first half. For women’s matches a significant, small reduction in running distance (p \u3c0.001) and a significant, small increase for walking distance (p \u3c0.001) was revealed during the second half compared to the first half. Significant, small to moderate differences were found between men’s and women’s matches for average speed (p = 0.006), running distance (p \u3c0.001), sprint distance (p \u3c0.001), and peak speed (p \u3c0.001). CONCLUSION: Findings show the physical demands of men’s touch rugby matches are more demanding than women’s matches. Results from our study suggest that gender specific conditioning programs should be implemented to ensure suitable preparation for international matches