Body Composition Asymmetry in University Rugby Players: Influence of Sex, Position, and Injury.

CONTEXT: Measures of side-to-side asymmetry in body composition may help identify players who are predisposed to lower limb injuries (LLI) or lower back pain (LBP). This study aimed to examine (1) side-to-side asymmetry in college rugby players according to sex and position and (2) whether side-to-side asymmetry is associated with LBP or LLI. DESIGN: Cross-sectional study. METHODS: Thirty-six rugby players (61% female) underwent a dual-energy X-ray absorptiometry assessment for total and regional (appendicular, truncal) outcomes of fat mass, lean mass, and bone mass. A subsample (n = 23) of players had a second dual-energy X-ray absorptiometry assessment 2 months postbaseline. Two-way analysis of variance was used to assess the effect of position (forward and backs) and sex on body composition asymmetry. Student paired t tests were used to assess side-to-side difference in body composition and compare baseline and follow-up measures. Logistic regression was used to assess possible associations between LLI, LBP, and the degree of side-to-side asymmetry in body composition. RESULTS: Male players had greater asymmetry in arm bone mass compared with female players (P = .026), and trunk fat mass asymmetry was greater in forwards as compared with backs (P = .017). Forwards had significantly greater fat mass (P = .004) and percentage of fat (P = .048) on the right leg compared with the left. Backs had significantly greater bone mass in the right arm compared with the left (P = .015). From baseline to postseason, forwards had a significant increase in side-to-side asymmetry in arm lean mass (P = .006) and a significant decrease in side-to-side asymmetry in leg fat mass (P = .032). In backs, side-to-side asymmetry at baseline compared with postseason was significantly different (P = .011) for trunk fat mass. There were no significant associations between body composition asymmetry, LLI, or LBP by sex or position. CONCLUSION: Our results revealed the presence of side-to-side asymmetries in body composition in university rugby players between sex and position. The amount of asymmetry, however, was not associated with LBP and LLI.

Integrating machine learning and digital microfluidics for screening experimental conditions.

Digital microfluidics (DMF) has the signatures of an ideal liquid handling platform - as shown through almost two decades of automated biological and chemical assays. However, in the current state of DMF, we are still limited by the number of parallel biological or chemical assays that can be performed on DMF. Here, we report a new approach that leverages design-of-experiment and numerical methodologies to accelerate experimental optimization on DMF. The integration of the one-factor-at-a-time (OFAT) experimental technique with machine learning algorithms provides a set of recommended optimal conditions without the need to perform a large set of experiments. We applied our approach towards optimizing the radiochemistry synthesis yield given the large number of variables that affect the yield. We believe that this work is the first to combine such techniques which can be readily applied to any other assays that contain many parameters and levels on DMF.

Body Composition Asymmetries in University Ice Hockey Players and Their Implications for Lower Back Pain and Leg Injury.

ABSTRACT: Resta, T, Frenette, S, Rizk, A, and Fortin, M. Body composition asymmetries in university ice hockey players and their implications for lower back pain and leg injury. J Strength Cond Res 36(10): 2830-2836, 2022-Right to left asymmetries in body composition have been examined across many sports, suggesting possible implications for lower back pain (LBP) and decreased level of performance. However, we are not aware of any study that has examined the presence and implications of morphological asymmetries in ice hockey players. The purpose of this study was to (a) investigate body composition asymmetries in female and male university-level ice hockey players and (b) examine whether the degree of body composition asymmetry is associated with the history of LBP and lower-limb injury (LLI). A total of 32 players (female = 18, male = 14) were included in this cross-sectional study (e.g., university research center setting). Dual-energy X-ray absorptiometry (DEXA) was used to acquire body composition measurements. The parameters of interest included bone mass, lean body mass, and fat mass, for the right and left sides and body segments (e.g., arm, leg, trunk, and total), separately. The history of LBP and LLI was obtained using a self-reported demographic questionnaire. The statistical significance for the study was set at p < 0.05. Our findings revealed significant side-to-side asymmetry in arm and total bone mass in females, with higher values on the right side. Both males and females also had significantly greater trunk lean body mass on the left side. With the exception of greater arm bone mass asymmetry being associated with LBP in the past 3 months, there was no other significant association between the degree of asymmetry with LBP and LLI. This study provides novel data regarding the presence of asymmetry in body composition in university-level ice hockey players. Monitoring body composition in athletes provides information that can be used by athletic trainers and strength and conditioning coaches to develop injury prevention, performance optimization, and targeted rehabilitation programs.

Seasonal Changes in Lumbar Multifidus Muscle in University Rugby Players.

PURPOSE: Although smaller lumbar multifidus muscle (LMM) was reported to be a strong predictor of lower limb injury (LLI) in Australian Football League players, LMM morphology has not been investigated in rugby athletes. This study examined seasonal changes in LMM in rugby players and whether LMM characteristics were associated with low back pain (LBP) and LLI. METHODS: Ultrasound examinations of the LMM were acquired in 21 university-level rugby players (12 women, 9 men) at preseason and end-season. LMM cross-sectional area (CSA), thickness at rest, and thickness during submaximal contraction (e.g., contralateral arm lift) measurements in prone and standing were obtained bilaterally at the L5-S1 level. The percent change in LMM thickness during contraction was calculated as follows: [(thicknesscontracted - thicknessrest)/thicknessrest × 100]. Self-reported questionnaires were used to acquire data on LBP and LLI. RESULTS: There was no significant difference in LMM characteristics between preseason and end-season measurements (P > 0.05). Preseason LMM CSA, side-to-side CSA asymmetry, and thickness at rest or during contraction were not associated with LBP or LLI. However, a lower percent thickness change in the standing position was significantly associated with having LBP during the preseason (P = 0.01) and playing season (P = 0.001), as well as LLI during the preseason (P = 0.03). CONCLUSIONS: This study provides preliminary evidence that LMM contractile ability and behavior during functional movement, such as standing, may have important implications for the susceptibility to injury among rugby athletes.

Lumbar Multifidus Muscle Characteristics, Body Composition, and Injury in University Rugby Players.

CONTEXT: A smaller lumbar multifidus (LM) muscle was reported to be a strong predictor of lower limb injury in professional Australian Football League players. However, despite the high prevalence of low back pain (LBP) and lower limb injury in rugby players, their LM characteristics have yet to be explored. OBJECTIVE: To (1) examine LM characteristics in male and female university rugby players and their possible associations with LBP and lower limb injury and (2) investigate the relationship between LM characteristics and body composition in this group of athletes. DESIGN: Cross-sectional study. SETTING: University research center. PATIENTS OR OTHER PARTICIPANTS: Thirty-four university rugby players (20 women, 14 men). MAIN OUTCOME MEASURE(S): Ultrasound measurements of LM cross-sectional area (CSA), thickness, and percentage change in thickness during contraction were obtained bilaterally, at the L5-S1 level, in prone and standing positions. Body composition measures were obtained using dual-energy x-ray absorptiometry. Self-reported questionnaires were used to obtain LBP and lower limb injury history. RESULTS: Players who reported LBP in the previous 3 months showed a smaller percentage change in thickness during contraction in the standing position (F = 5.21, P = .03). The LM CSA side-to-side asymmetry (right versus left) was greater in players who reported having a lower limb injury in the previous 12 months (F = 4.98, P = .03). The LM CSA was significantly associated with body composition measurements. A greater percentage change in thickness during contraction was significantly associated with a lower percentage of body fat. The LM echo intensity was strongly associated with the total percentage of body fat and was significantly greater in women. CONCLUSIONS: The influence of body composition on LM morphology in athletes cannot be ignored and warrants further investigation. Our findings also provide preliminary evidence of an association among LM morphology, LBP, and lower limb injury in university rugby players.

The effect of low back pain and lower limb injury on lumbar multifidus muscle morphology and function in university soccer players.

BACKGROUND: The lumbar multifidus muscle (LMM) plays a critical role to stabilize the spine. While low back pain (LBP) is a common complaint in soccer players, few studies have examined LMM characteristics in this athletic population and their possible associations with LBP and lower limb injury. Therefore, the purpose of this study was to 1) investigate LMM characteristics in university soccer players and their potential association with LBP and lower limb injury; 2) examine the relationship between LMM characteristics and body composition measurements; and 3) examine seasonal changes in LMM characteristics. METHODS: LMM ultrasound assessments were acquired in 27 soccer players (12 females, 15 males) from Concordia University during the preseason and assessments were repeated in 18 players at the end of the season. LMM cross-sectional area (CSA), echo-intensity and thickness at rest and during contraction (e.g. function) were assessed bilaterally in prone and standing positions, at the L5-S1 spinal level. A self-reported questionnaire was used to assess the history of LBP and lower limb injury. Dual-energy x-ray absorptiometry (DEXA) was used to acquire body composition measurements. RESULTS: Side-to-side asymmetry of the LMM was significantly greater in males (p = 0.02). LMM thickness when contracted in the prone position (p = 0.04) and LMM CSA in standing (p = 0.02) were also significantly greater on the left side in male players. The LMM % thickness change during contraction in the prone position was significantly greater in players who reported having LBP in the previous 3-months (p < 0.001). LMM CSA (r = - 0.41, p = 0.01) and echo-intensity (r = 0.69, p < 0.001) were positively correlated to total % body fat. There was a small decrease in LMM thickness at rest in the prone position over the course of the season (p = 0.03). CONCLUSIONS: The greater LMM contraction in players with LBP may be a maladaptive strategy to splint and project the spine. LMM morphology measurements were correlated to body composition. The results provide new insights with regards to LMM morphology and activation in soccer players and their associations with injury and body composition measurements.

Ultrasonography of Lumbar Multifidus Muscle in University American Football Players.

PURPOSE: The primary objective of this study was to examine and compare lumbar multifidus (LM) muscle size, asymmetry, and function in university football players with and without low back pain (LBP). A secondary objective was to examine the relationship between LM characteristics and body composition in football players. METHODS: Ultrasound assessments of the LM muscle were performed in 41 university football players during the preseason. LM muscle cross-sectional area, echo intensity (e.g., indicator of fatty infiltration and connective tissue), thickness at rest, and thickness during submaximal contraction (e.g., contralateral arm lift) measurements in prone and standing positions were obtained bilaterally at the L5-S1 level. Body composition measures were acquired using dual-energy x-ray absorptiometry. A self-administered questionnaire was used to obtain LBP history data. RESULTS: The LM muscle thickness at rest in prone and in standing was significantly smaller in football players who reported the presence of LBP in the previous 3 months. The LM cross-sectional area in prone was significantly and positively correlated with weight, height, lean body mass, total fat mass, and total percent body fat. LM echo intensity was strongly correlated with total percent body fat and total fat mass and negatively correlated with the percent thickness change during contraction. CONCLUSION: The results of this study provide novel information on LM muscle morphology and activation in football players in prone and standing and suggest that players with LBP in the previous 3 months had smaller LM muscle thickness. LM morphology was strongly correlated with body composition measurements.

Ultrasonography of multifidus muscle morphology and function in ice hockey players with and without low back pain.

OBJECTIVES: To examine the relationship between lumbar multifidus (LM) morphology, function, echo-intensity (EI) and body composition among a group of university level ice hockey players with and without low back pain (LBP). DESIGN: Cross-sectional study. SETTING: University Research Centre. PARTICIPANTS: Thirty-two hockey players (18 females, 14 males) participated in this study. MAIN OUTCOME MEASURES: Resting LM cross-sectional area (CSA) was assessed bilaterally at the L5 level in prone and standing using ultrasound imaging. The LM thickness at rest and during contraction was evaluated in addition to LM EI. Body composition measures were acquired using dual-energy X-ray absorptiometry (DEXA) and LBP history was acquired using a self-reported questionnaire. RESULTS: LM muscle CSA was significantly associated with body composition measurements. LM EI was strongly associated with total % body fat and significantly greater in females. Resting LM muscle CSA and thickness (prone) was significantly smaller in players with LBP 4-weeks prior. LM side-to-side asymmetry (standing) was also significantly greater in players with LBP 3-months prior. CONCLUSION: The results provide new insights with regards to LM morphology and activation in ice hockey players and revealed specific deficits in LM morphology in athletes with LBP. LM morphology was strongly associated with body composition measurements.