KINETIC ASYMMETRY AND CENTER OF MASS DISPLACEMENT DURING JUMPS

The purpose of this study was to determine the role of kinetic asymmetry on center of mass displacement in both mediolateral (COMd ML) and anteroposterior directions (COMd AP). Seventeen collegiate baseball players underwent weight distribution (WtD), and unloaded and loaded static (SJ) and countermovement jumps (CMJ). Concurrent kinetic and kinematic data were collected during the evaluation. Independent samples t tests were run to evaluate differences in COMd between the most and least asymmetrical athletes. WtD was not able to differentiate between values of COMd AP, but did for loaded conditions of COMd ML. Peak force and rate of force development (RFD) asymmetry appear to influence COMd, and RFD asymmetry appears to show the most differentiability between groups in terms of COMd ML. Kinetic asymmetry may result in undesirable displacement of athletes’ COM during jumping

LEG DYNAMIC STRENGTH PREDICTORS OF A PRE-PLANNED CHANGE OF DIRECTION TASK IN NCAA DIVISION I SOCCER PLAYERS

The purpose of this investigation was to evaluate the relationships between two types of vertical jumps and change of direction (COD) test in collegiate soccer players (n=24). 5-5 COD test was utilized to measure soccer athletes’ COD ability. 3m acceleration (3mAcc), Total time (TT) and Partial time (PT) were measured by two sets of timing gates. Countermovement jump (CMJ) and static jump (SJ) with 2 different loading conditionings (0kg and 20kg) were employed to evaluate athletes’ leg dynamic strength. Strong statistically significant relationships were found between COD test variables (r =0.71 to 0.90), and between vertical jump variables with PT and TT (r = -0.41 to -0.81). These results suggest that leg dynamic strength is vital for NCAA Division I soccer players’ COD performance and SJ 0kg jump height can be used to predict for COD performance

THE RELATIONSHIP OF FORCE PRODUCTION ASYMMETRY AND PERFORMANCE IN ATHLETES OF DIFFERENT STRENGTH LEVELS

The purpose of this study was to evaluate the relationship between force production asymmetry and performance of athletes with differing strength levels in males and females. Collegiate athletes (n=129) from various sports were ranked according to isometric mid-thigh pull peak force and the top (‘strong’) and bottom (‘weak’) 25% were used for analysis. Symmetry index (SI) scores were calculated and correlated with their respective force-time characteristics using bivariate correlations. For the weaker males, several negative moderate correlations were observed; however, no statistically significant correlations were observed for the females in either group. These findings indicate that force production asymmetry is inversely related to performance in weaker male athletes during isometric strength testing; however, similar to previous findings, this relationship is not apparent in stronger males

USING KINETIC ISOMETRIC MID-THIGH PULL VARIABLES TO PREDICT D-I MALE SPRINTERS’ 60M PERFORMANCE

The purpose of the study was to determine the relationship of isometric mid-thigh pull kinetic variables including: peak force (PF), instantaneous force at 50, 90, 200 and 250 milliseconds (F@50, 90, 200 and 250 ms) rate of force development (RFD@ 50, 90, 200 and 250 ms) and impulse at 50, 90, 200, and 250 ms (IP @ 50, 90, 200 and 250 ms) to college male sprinters’ 60 m running performance. Eleven NCAA Division I male sprinters participated in the study that included two testing sessions. The first session included sprint testing and the second session included isometric mid-thigh pull strength assessment. The results from current study indicated that explosive force production variables (F@ 50 ms, RFD @ 50 and 90 ms, IP @ 90 and 200 ms) showed strong correlations with 60 m running time and maximal running velocity; while the MPF was not related to sprint variables

Guest Recital: Obohio

Kemp Recital Hall Thursday Evening October 29, 1992 8:00p.m

The Effects of Strength Training on Isometric Force Production Symmetry in Recreationally Trained Males

Objectives: The purpose of this investigation was to determine what effect a bilateral strength training regimen has on isometric force production symmetry and if changes in force production symmetry can be accounted for by differences in pre-intervention strength levels. Design: Sixteen recreationally trained males (1-RM squat: 146.8 ± 23.0 kg.) were assigned to two groups for the 7-week training intervention: strong (S) and weak (W) based on pre-training squat isometric peak force allometrically scaled (IPFa) at 120° knee angle. Methods: Subjects completed a 7-week training intervention following a block-periodized model and were tested on measures of dynamic (1RM squat) and isometric (isometric squat at 90° and 120° knee angle) strength pre- and post-intervention. The degree of bilateral lower limb asymmetry was calculated as a percentage where 0% symmetry index (SI) indicates perfect symmetry on the isometric squat.Results: ANCOVA results showed no statistical difference between groups for all dependent variables when pre-intervention IPFa 120° scores were used as the covariate. Paired t-tests results showed both groups statistically improved 1RM squat and IPFa 120° (p \u3c 0.05). IPFa 120° SI decreased statistically from pre-training in the W group (p = 0.03). Independent t-test results showed the W group had statistically larger pre-intervention SI scores for IPFa 90° (p = 0.045) and IPFa 120° (p = 0.007); however this difference was no longer present following strength training. There was a strong inverse relationship between pooled IPFa 120° and IPFa 120° SI (r = -0.64, p = 0.004). Conclusions: The findings of the current study support the notion that weaker individuals can augment lower limb symmetry with strength training. The same does not seem to be true for stronger individuals who already have a low symmetry index score. These findings indicate that strength training improves force production symmetry in relatively weak males, which may be important for bilateral tasks and injury potential reduction

The Relationship of Force Production Asymmetry and Performance in Athletes of Different Strength Levels

The purpose of this study was to evaluate the relationship between force production asymmetry and performance of athletes with differing strength levels in males and females. Collegiate athletes (n=129) from various sports were ranked according to isometric mid-thigh pull peak force and the top (‘strong’) and bottom (‘weak’) 25% were used for analysis. Symmetry index (SI) scores were calculated and correlated with their respective force-time characteristics using bivariate correlations. For the weaker males, several negative moderate correlations were observed; however, no statistically significant correlations were observed for the females in either group. These findings indicate that force production asymmetry is inversely related to performance in weaker male athletes during isometric strength testing; however, similar to previous findings, this relationship is not apparent in stronger males

Leg Dynamic Strength Predictors of a Pre-Planned Change of Direction Task in NCAA Division 1 Soccer Players

The purpose of this investigation was to evaluate the relationships between two types of vertical jumps and change of direction (COD) test in collegiate soccer players (n=24). 5-5 COD test was utilized to measure soccer athletes’ COD ability. 3m acceleration (3mAcc), Total time (TT) and Partial time (PT) were measured by two sets of timing gates. Countermovement jump (CMJ) and static jump (SJ) with 2 different loading conditionings (0kg and 20kg) were employed to evaluate athletes’ leg dynamic strength. Strong statistically significant relationships were found between COD test variables (r =0.71 to 0.90), and between vertical jump variables with PT and TT (r = -0.41 to -0.81). These results suggest that leg dynamic strength is vital for NCAA Division I soccer players’ COD performance and SJ 0kg jump height can be used to predict for COD performance

Body of evidence: forensic use of baseline health assessments to convict wildlife poachers

CONTEXT. Given the immense impact of wildlife trade, disease and repatriations on populations, health assessments can" "provide powerful forensic material to help convict wildlife poachers and minimise risks of releasing unhealthy wildlife." AIMS. We aimed to use reference ranges to assess the health of confiscated tortoises, to illustrate forensic application of these ranges, and to advance analyses for future applications." METHODS. We used analyses of variance (ANOVA) and covariance (ANCOVA), and composite indices, to compare wild and confiscate tortoise body condition, haematocrit and haemoglobin concentration of males and females of three tortoise species. Subsequently, we used multivariate statistics (e.g. discriminant analyses) to evaluate the relative importance of species, sex and group (wild or confiscate) on tortoise condition and haematology." KEY RESULTS. Our initial statistical tests demonstrated, at P < 0.05 to P < 0.0005, that confiscate body condition and haematology were compromised compared with that of wild tortoises. Subsequently, discriminant analyses strongly discriminated between most wild and confiscate groups (P < 0.0001), correctly classified individual health as wild or confiscate 80–90% of the time, indicated that species and sex effects were stronger than was the wild-confiscate category, and provided discriminant functions for use on other taxa and studies." CONCLUSIONS. The health assessments discriminated well between wild and confiscate tortoises. The results had considerable forensic value, being relevant, quickly generated using portable field equipment, reliable, accurate, easy to explain and convey in terms of likelihood in a court of law, synergistically consistent among variables and groups, a strong rebuttal to the poachers’ specific statements, and consistent with other types of evidence. Multivariate analyses were consistent with, and more prudent and powerful than, the original statistical analyses. Discriminant functions can be applied in future studies and on other chelonian species, and should be developed for other wildlife species." IMPLICATIONS. Reference ranges provide considerable value for forensics, diagnostics and treatment. Given the disease risks resulting from the massive scale of wildlife trade and release, reference ranges should be developed for more species."Web of Scienc

Selenium deficiency is widespread and spatially dependent in Ethiopia

Selenium (Se) is an essential element for human health and livestock productivity. Globally, human Se status is highly variable, mainly due to the influence of soil types on the Se content of crops, suggesting the need to identify areas of deficiency to design targeted interventions. In sub-Saharan Africa, including Ethiopia, data on population Se status are largely unavailable, although previous studies indicated the potential for widespread Se deficiency. Serum Se concentration of a nationally representative sample of the Ethiopian population was determined, and these observed values were combined with a spatial statistical model to predict and map the Se status of populations across the country. The study used archived serum samples (n = 3269) from the 2015 Ethiopian National Micronutrient Survey (ENMS). The ENMS was a cross-sectional survey of young and school-age children, women and men. Serum Se concentration was measured using inductively coupled plasma mass spectrometry (ICPMS). The national median (Q1, Q3) serum Se concentration was 87.7 (56.7, 123.0) μg L−1. Serum Se concentration differed between regions, ranging from a median (Q1, Q3) of 54.6 (43.1, 66.3) µg L−1 in the Benishangul-Gumuz Region to 122.0 (105, 141) µg L−1 in the Southern Nations, Nationalities, and Peoples’ Region and the Afar Region. Overall, 35.5% of the population were Se deficient, defined as serum Se < 70 µg L−1. A geostatistical analysis showed that there was marked spatial dependence in Se status, with serum concentrations greatest among those living in North-East and Eastern Ethiopia and along the Rift Valley, while serum Se concentrations were lower among those living in North-West and Western Ethiopia. Selenium deficiency in Ethiopia is widespread, but the risk of Se deficiency is highly spatially dependent. Policies to enhance Se nutrition should target populations in North-West and Western Ethiopi