Recreational Female Athletes Research Articles

The relationship between low energy availability, injuries, and bone health in recreational female athletes.

Low energy availability (LEA) causes pathophysiology of the female athlete's body affecting the bone and reproductive health and was observed to have a high prevalence in recreational female athletes previously. The aim of this study was to analyse the relationship between low energy availability in females questionnaire (LEAF-Q), bone mineral density (BMD), and postural stability in recreational athletes. Recreational female athletes (n = 24, age: 23.71 ± 2.94, Tier I) completed LEAF-Q, postural stability measurement during quiet stance (Zebris platform FDM; GmbH) and their BMD was measured using DXA (Hologic QDR Horizon A). Non-parametric statistical tests were used to analyse the relationships between LEAF-Q, BMD, and postural stability and to compare differences between participants divided by the LEAF-Q score and its subscales. Risk of LEA was observed in 50% of recreational athletes participating in this study. Up to 46% of participants perceived menstrual bleeding changes related to training and 37.50% experienced menstrual dysfunction. Body composition and body weight fluctuations were observed to affect postural stability and BMD. With the risk score for LEA, the BMD and postural stability were not negatively affected in recreational athletes. However, the high number of recreational athletes in the risk score for LEA and menstrual dysfunctions highlights the need for public health programs aimed to increase awareness of LEA and its health consequences and for open communication about the menstrual cycle. Future longitudinal studies observing LEA, BMD, menstrual function, postural stability, and their interrelationship in female athletes are needed to increase the knowledge of this topic.

Recreational Female Athletes’ Understanding of and Perceived Impact of the Menstrual Cycle on Physical Performance, Mood, and Sleeping Behaviour

This study aimed to examine female recreational (FRC) athletes’ knowledge of the menstrual cycle and their perception of how each phase affects their performance, mood, and sleep. One hundred and sixty-four (n = 164) FRC athletes completed an online survey. The questionnaire employed was based on previously validated questionnaires and consisted of three different sections: (a) knowledge about the menstrual cycle, (b) menstrual cycle symptoms, and (c) menstrual cycle and performance. The results indicated that 70.1% of the surveyed FRC athletes were not knowledgeable regarding the phases of the menstrual cycle, with 55.5% being ignorant of the specific hormones released during the cycle. Furthermore, 37.8% perceived that their performance was sometimes affected during the early follicular phase, with the main symptoms being physical fatigue (17.9%) and a more irritable mood (25.9%). In addition, 19.5% of the FRC athletes reported sleeping disturbances, and 20.4% described changes in sleep quality during menstruation. Lastly, 11.9% of the FRC athletes reported suffering from a combination of mood swings, sleeping problems, bloating or stomach issues, breast tenderness, headaches, and fatigue prior to menstruation. The results of this study provide valuable insights into how FRC athletes experience the menstrual cycle, which can help RC athletes and trainers better understand their needs and support them in achieving optimal performance.

Effect of increased protein intake and exogenous ketosis on body composition, energy expenditure and exercise capacity during a hypocaloric diet in recreational female athletes.

Introduction: Since low body weight is an important determinant of success in many sports such as gymnastics, martial arts and figure skating, athletes can benefit from effective weight loss strategies that preserve muscle mass and athletic performance. The present study investigates the effects of increased protein intake and exogenous ketosis on body composition, energy expenditure, exercise capacity, and perceptions of appetite and well-being during a hypocaloric diet in females. Methods: Thirty-two female recreational athletes (age: 22.2 ± .5years; body weight: 58.3 ± .8kg; BMI: 20.8 ± .2kg·m-2) underwent 4 weeks of 30% caloric restriction and were randomized to receive either an increased daily amount of dietary protein (PROT, ∼2.0-2.2g protein·kg-1·day-1), 3 × 20g·day-1 of a ketone ester (KE), or an isocaloric placebo (PLA). Body composition was measured by DXA, resting energy expenditure (REE) by indirect calorimetry, exercise capacity during a VO2max test, appetite hormones were measured in serum, and perceptions of general well-being were evaluated via questionnaires. Results: The hypocaloric diet reduced body weight by 3.8 ± .3kg in PLA, 3.2 ± .3kg in KE and 2.4 ± .2kg in PROT (Ptime<.0001). The drop in fat mass was similar between treatments (average: 2.6 ± .1kg, Ptime<.0001), while muscle mass was only reduced in PLA and KE (average: .8 ± .2kg, Ptime<.05), and remained preserved in PROT (Pinteraction<.01). REE [adjusted for lean mass] was reduced after caloric restriction in PLA (pre: 32.7 ± .5, post: 28.5 ± .6kcal·day-1·kg-1) and PROT (pre: 32.9 ± 1.0, post: 28.4 ± 1.0kcal·day-1·kg-1), but not in KE (pre: 31.8 ± .9, post: 30.4 ± .8kcal·day-1·kg-1) (Pinteraction<.005). Furthermore, time to exhaustion during the VO2max test decreased in PLA (by 2.5 ± .7%, p < .05) but not in KE and PROT (Pinteraction<.05). Lastly, the perception of overall stress increased in PLA and PROT (p < .05), but not in KE (Pinteraction<.05). Conclusion: Increased protein intake effectively prevented muscle wasting and maintained exercise capacity during a period of caloric restriction in female recreational athletes. Furthermore, exogenous ketosis did not affect body composition, but showed its potential in weight management by preserving a drop in exercise capacity and REE and by improving overall stress parameters during a period of caloric restriction.

Effect of external isometric hip rotation force on lower extremity muscles activities during pelvic drop with different hip positions

Gluteus medius muscle (Gmed) dysfunction has been confirmed as a functional defect in subjects with Genu Valgum Deformity (GVD). The purpose of this study was to determine whether the change in the positions of hip rotation and applying isometric hip external rotation during pelvic drop (PD) can affect muscles activity in subjects with GVD. A total of thirty recreational female athletes with (n = 15) and without (n = 15) GVD participated in this study. Surface electromyography measured Gmed, tensor fascia latae (TFL), and quadratus lumborum (QL) muscles activity when subjects performed PD in three different positions of hip rotations with and without applied isometric hip external rotation force. There were differences in muscle activity between GVD and healthy subjects. The Gmed/TFL and Gmed/QL muscles activity ratio altered while placing the hip in different rotation positions and applying isometric load. The lower extremity muscles’ activity is affected by GVD, and changing the positions of the hip rotation in the PD task can be associated with altered muscle activity in both GVD and healthy Groups. However, applying isometric hip external rotation during PD can be suggested as an effective intervention to increase Gmed activity.

Is the Side Bridge Test Valid and Reliable for Assessing Trunk Lateral Flexor Endurance in Recreational Female Athletes?

Simple SummaryAlthough the side bridge test has been widely used for assessing trunk lateral flexor endurance in sport, clinical, and scientific settings, to the best of the authors’ knowledge, no study has analyzed its validity and reliability in an only female population. The surface electromyography of eight abdominal, back, shoulder and hip muscles was measured during the test to analyze its validity. A one-week test-retest design was performed to evaluate its reliability. No significant differences were found between the trunk lateral flexors and the deltoids. The study data showed that the test performance could be significantly predicted by external oblique and deltoid normalized median frequency slopes and by body mass and trunk height. Based on the results of this study, the shoulder muscle activation and fatigue and the individuals’ anthropometric characteristics, especially the mass, played an important role in the side bridge test performance, which questions the validity of this multi-joint test to specifically assess trunk lateral flexor endurance. In addition, although the side bridge test showed a good data consistency, its intra-subject variability was high, which reduces its utility when small intra-subject changes in muscle endurance are important (e.g., elite sport).The side bridge test (SBT) is one of the most popular tests to assess isometric trunk lateral flexor endurance. The aim of this study was to assess the validity and reliability of the SBT in healthy females. Twenty-four (24.58 ± 3.92 years) physically active (1–2 h of moderate physical activity, 2–3 times a week) females voluntarily participated in this study. The surface electromyography (EMG) of eight abdominal, back, shoulder and hip muscles was measured during the SBT. Normalized median frequency slopes (NMFslope) were calculated to analyze the muscle fatigue. The EMG amplitudes were normalized to maximum EMG values to assess muscle activity intensity. A one-week test-retest design was performed to evaluate the SBT reliability through the ICC3,1 and typical error. Higher NMFslopes and normalized EMG amplitudes were found in deltoids, abdominal obliques, rectus abdominis, and erector spinae in comparison to latissimus dorsi, gluteus medius, and rectus femoris. However, no significant differences were found between the trunk lateral flexors and the deltoids. Linear regression analysis showed that SBT performance could be significantly predicted by external oblique and deltoid NMFslope (adjusted R2 = 0.673) and by body mass and trunk height (adjusted R2 = 0.223). Consistency analysis showed a high intraclass correlation coefficient (0.81) and a relatively high typical error (10.95 s). Despite the good relative reliability of the SBT, its absolute reliability was low and its validity questionable, as the shoulder muscle activation and fatigue and the individuals’ anthropometric characteristics played an important role in SBT performance.

Impact of sports on temporomandibular dysfunction: a comparison of competitive and recreational female athletes as well as female non-athletes

ObjectivesThe present study was conducted to investigate the correlation between (competitive) sports and the occurrence of temporomandibular dysfunctions (TMD) by comparing the prevalences in competitive, recreational, and non-athletic women.Materials and methodsA total of 138 women between the ages of 18 and 45 were interviewed about symptoms of TMD by means of a questionnaire. Based on their athletic performance level, the participating women were classified as competitive athletes, recreational athletes, or non-athletes (each group n = 46).ResultsSymptoms of TMD were notably less frequent in competitive female athletes (52.2%) than in recreational female athletes (63.0%) and female non-athletes (60.9%). With increasing training load, the prevalence of TMD decreased in both the competitive and recreational female athlete groups.ConclusionsAthletic activity in general seems to have a positive effect on the occurrence of TMD. Competitive female athletes appear less likely to suffer from symptoms of TMD than recreational athletes and non-athletes. One possible explanation for this could be the better supervision by qualified trainers and physiotherapists in competitive sports.Clinical relevancePatients should be motivated to engage in sports as a protective measure against symptoms of TMD. However, it is important to ensure that they are properly instructed by experienced personnel in order to avoid unphysiological strain and negative consequences.

Recreational Female Athletes Scored Higher on the Landing Error Scoring System-Real Time

Objective: There is no study examining the difference of LESS-RT (Landing Error Scoring System-real time) score according to gender. This study aimed to address this precise question. Methods: The study included recreational athletes aged 18-25 years who did not have a history of musculoskeletal injury in the last 6 months or surgery or fracture in the last 24 months, and who were classified as active according to the General Practice Physical Activity Questionnaire. Participants were evaluated using the LESS-RT. Jump-landing errors were evaluated in real-time by a sports medicine specialist. Results: The study included 55 healthy individuals (28 females, 27 males) with an average age of 21.8 ± 1.1 years. The two sexes were not significantly different in terms of age (p=0.572). For all participants, the mean LESS-RT score was 6.93 ± 1.99. Females scored significantly higher than males (7.61 ± 1.81 vs. 6.22 ± 1.97, p=0.009). However, the LESS-RT scores were not significantly correlated with anthropometric characteristics, such as age, height, body weight, or BMI, according to sex (p&gt;0.05). Females scored higher on LESS-RT (i.e. poorer performance), (p= 0.007). Conclusion: Female athletes scored higher on LESS-RT. Athletes, especially females, should be assessed for biomechanical errors in jump-landing.

Influence of Higenamine on Exercise Performance of Recreational Female Athletes: A Randomized Double-Blinded Placebo-Controlled Trial.

The aim of this study was to determine the ergogenic effects and the safety profile of a one-component higenamine supplement in female recreational athletes. Twelve recreational female basketball players (age 29–41 years, oxygen consumption (VO2max) > 30 ml⋅kg–1⋅min–1, with training > 5 h wk–1) were randomized either to the higenamine group, or to the placebo group for 3 weeks. In order to determine ergogenic effects and safety profile of higenamine administration, we assessed the following variables before and after 3 weeks of supplementation: anthropometric parameters, resting metabolic rate (RMR), exercise testing variables, serum free fatty acids (FFAs), blood pressure, enzyme activity, urea, lipid profile, and complete blood count. There were no differences between groups in anthropometric parameters, including basal metabolic rate (BMR), RMR and body fat [p = 0.706 (Cohen’s d 0.223), p = 0.169 (Cohen’s d 0.857), and p = 0.223 (Cohen’s d 0.750), respectively], FFAs [0.43 ± 0.03 vs. 0.54 ± 0.23, p = 0.206 (Cohen’s d 0.540)], neither significant differences in cardiopulmonary parameters after the intervention period. Furthermore, all measured outcome variables in the safety assessment were not significant, with values remaining stable during the intervention period for participants in both groups. This is the first study to document the effects and the safety profile of higenamine-based dietary supplements at a specified dose in female recreational athletes. Our data indicate that 21-day of supplementation with 75 mg higenamine would not result in improving cardiopulmonary exercise fitness and weight loss in female recreational athletes. Moreover, supplementation with 75 mg higenamine is safe and well-tolerated in younger recreational female athletes.

Risk Factors For Relative Energy Deficiency In Sport In Costa Rican Recreational Female Athletes

Risk Factors For Relative Energy Deficiency In Sport In Costa Rican Recreational Female Athletes

Prevalence of disordered eating, eating disorders and risk of low energy availability in professional, competitive and recreational female athletes based in the United Kingdom

ABSTRACT Eating disorders (ED), disordered eating (DE) and low energy availability (LEA) can be detrimental to health and performance. Previous studies have independently investigated the prevalence of ED, DE or LEA; however, few combined methods have identified risk within female athletes. The aim of this study was to identify the prevalence of ED, DE and LEA in UK-based female athletes and investigate whether associations exist between age, competition level and primary sport. The Female Athlete Screening Tool (FAST) and Low Energy Availability in Females Questionnaire (LEAF-Q) were used in a cross-sectional study design. A total of 112 responses eligible for analysis were received. A total of 16%, 44% and 53% of female athletes were at risk of ED (FAST: >94), DE and LEA, respectively. Competition level (recreational, competitive or professional athletes; fishers, p ≤ 0.05) influenced and was a predictor of FAST (R 2 = 0.076, F (1,110) = 10.067, p ≤ 0.05, variance inflation value; VIF = 1.0) whereas age influenced (age: H (2) = 13.128, p ≤ 0.05), and was a predictor (R 2 = 0.144, F (2,109) = 9.170, p ≤ 0.05, VIF = 1.0) of LEAF-Q. A positive correlation was observed between FAST and LEAF-Q scores (R = 0.496, p ≤ 0.05). Age and competition level may be predicting risk factors of ED/DE and LEA within female athletes; however, further research is required to support the findings of this present study.

A - 30 Executive Function in Division-I Collegiate Athletes and Recreationally Active College Students

Abstract Objective High-level cognitive performance is important for navigating the complex environment of sport. The executive function domain may be of particular importance because it focuses on flexible thinking and self-control. It is unclear if high-level athletes exhibit similar executive function compared to recreational athletes. Therefore, the purpose of this study was to compare executive function between male and female Division-I collegiate athletes and recreationally active peers. Methods Thirty-seven Division-I athletes (16 females, 21 males) and 30 recreationally active college students (19 females, 11 males) participated. Participants completed the Flanker Inhibitory Control and Attention Test (FICA) and Dimensional Change Card Sort Test (DCCS) from the National Institute of Health Toolbox Cognitive Battery on a tablet to assess cognitive flexibility and attention and inhibitory control, respectively. Demographically-corrected T-scores were used for analysis. Two-way ANOVAs compared cognitive performance based on group and sex (p ≤ 0.05). Results There was a significant group-by-sex interaction for the FICA (p = 0.005). Female recreational athletes (50.68 ± 10.18) demonstrated higher FICA scores compared to female Division-I athletes (40.88 ± 7.35; p = 0.003, ES = 1.06). Male Division-I athletes (48.67 ± 10.39) also exhibited greater scores compared to female Division-I athletes (p = 0.015, ES = 0.83). There was no significant group-by-sex interaction (p = 0.84), group effect (p = 0.35), or sex effect (p = 0.43) for the DCCS. Conclusions Female Division-I athletes demonstrated poorer performance on the FICA compared to male Division-I athletes and recreational female athletes which may indicate a decreased ability to suppress motor responses caused by internal or external distractions. The significance of these findings for mitigating injury risk and improving athletic performance should be explored.

Methodological Approach of the Iron and Muscular Damage: Female Metabolism and Menstrual Cycle during Exercise Project (IronFEMME Study).

Background: The increase in exercise levels in the last few years among professional and recreational female athletes has led to an increased scientific interest about sports health and performance in the female athlete population. The purpose of the IronFEMME Study described in this protocol article is to determine the influence of different hormonal profiles on iron metabolism in response to endurance exercise, and the main markers of muscle damage in response to resistance exercise; both in eumenorrheic, oral contraceptive (OC) users and postmenopausal well-trained women. Methods: This project is an observational controlled randomized counterbalanced study. One hundered and four (104) active and healthy women were selected to participate in the IronFEMME Study, 57 of which were eumenorrheic, 31 OC users and 16 postmenopausal. The project consisted of two sections carried out at the same time: iron metabolism (study I) and muscle damage (study II). For the study I, the exercise protocol consisted of an interval running test (eight bouts of 3 min at 85% of the maximal aerobic speed), whereas the study II protocol was an eccentric-based resistance exercise protocol (10 sets of 10 repetitions of plate-loaded barbell parallel back squats at 60% of their one repetition maximum (1RM) with 2 min of recovery between sets). In both studies, eumenorrheic participants were evaluated at three specific moments of the menstrual cycle: early-follicular phase, late-follicular phase and mid-luteal phase; OC users performed the trial at two moments: withdrawal phase and active pill phase. Lastly, postmenopausal women were only tested once, since their hormonal status does not fluctuate. The three-step method was used to verify the menstrual cycle phase: calendar counting, blood test confirmation, and urine-based ovulation kits. Blood samples were obtained to measure sex hormones, iron metabolism parameters, and muscle damage related markers. Discussion: IronFEMME Study has been designed to increase the knowledge regarding the influence of sex hormones on some aspects of the exercise-related female physiology. Iron metabolism and exercise-induced muscle damage will be studied considering the different reproductive status present throughout well-trained females’ lifespan. Trial registrationThe study was registered at Clinicaltrials.gov NCT04458662 on 2 July 2020.

Influence of the Menstrual Cycle Phase on Marathon Performance in Recreational Runners

To examine the potential impact of fluctuations in sex steroid hormones across the menstrual cycle (MC) on marathon running performance of recreational female athletes. A survey questionnaire was administered to recreational, nonelite runners who had completed multiple marathons within the last 18 months. A total of 599 questionnaires were returned and deemed viable for review. From these, 185 survey participants were found to have complete information and eligibility to have their surveys used in the statistical analysis. A total of 106 women had their best marathon performance in the luteal phase (high sex steroid hormones) of the MC, and 79 had their best performance in the follicular phase (low sex steroid hormones) of the MC (responses were significantly different; z-score value = 1.11; P < .05). Recreational female runners have varying performances in the marathon across their MC phases, specifically performing better in the luteal phase of the cycle.

Effect of herbal antioxidant-rich formula on improvement of antioxidant defense system and heat shock protein-70 expression in recreational female athletes: A randomized controlled trial

Background:The aim of the present study was to evaluate the effect of natural antioxidant formula (blend of herbs: ginger root, cinnamon bark and raw almond fruit powder, rosemary leaf powder, and honey) on oxidative status, antioxidant enzyme activity, and relative heat shock protein (HSP-70) expression in recreational female athletes.Materials and Methods:Eighteen female participants trained for 4 weeks and randomly received either antioxidant formula (FormEX) (n = 8) or placebo (PlcEX) (n = 10) in a randomized controlled trial. Blood samples were obtained 1-h before, 1 h and 24 h postexercise to measure malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidases (GPx), and HSP70 mRNA expression. Data analysis was performed using 2 (treatment = grouping factor) ×6 (time = within-factor) repeated measurements analysis of variance or generalized estimating equations (GEE) test. We used the independent t-test to evaluate any significant differences for real-time polymerase chain reaction data.Results:Antioxidant formula increased the relative HSP-70 mRNA expression more than Plc-EX group in all time points (P = 0.001). The time main effect was significant with regard to TAC and SOD concentrations (P = 0.001 and 0.002, respectively). However, there were no statistically significant differences between groups for TAC, SOD, and MDA (P = 0.25, 0.06, and 0.38, respectively). Neither the time main effect for MDA nor time and intervention interaction was not statistically significant for MDA, TAC, and SOD (P = 0.19, 0.13, and 0.10, respectively). GEE results for GPx showed that there were no significant differences between the groups (P = 0.11).Conclusion:The results presented herein revealed that natural antioxidant rich formula had variable effects on oxidative status. However, in contrast to many antioxidant supplements, this formulation increases the HSP-70 mRNA expression which might improve the antioxidant ability of cells in the long-term period and exercise-induced adaptation.

Association of Hip and Trunk Strength With Three-Dimensional Trunk, Hip, and Knee Kinematics During a Single-Leg Drop Vertical Jump.

Martinez, AF, Lessi, GC, Carvalho, C, and Serrao, FV. Association of hip and trunk strength with three-dimensional trunk, hip, and knee kinematics during a single-leg drop vertical jump. J Strength Cond Res 32(7): 1902-1908, 2018-Kinematic changes have been correlated with different lower-limb injuries. Movement is influenced by multiple factors and strength is one of the contributors that can influence it. Thus, the aim of this study was to evaluate the correlation among trunk and hip isometric strength with trunk and lower-limb kinematics during a single-leg drop vertical jump. Twenty-three healthy recreational female athletes aged between 18 and 35 years underwent isometric evaluation of hip abductor, hip extensor, and lateral trunk muscle strength and 3-dimensional trunk and lower-limb kinematics during a single-leg drop vertical jump. Pearson's correlation coefficients (r) were calculated to establish the association among hip and trunk strength and trunk, hip, and knee kinematics. As result, no significant correlations were found between the peak and movement excursion values of kinematic and hip and trunk isometric strength data. The lack of correlation between isometric strength and kinematics in healthy female athletes indicates that intervention programs should not be focused solely on strength exercises to influence the movement pattern during single-landing activities.

Effects of Eight Weeks of Self-Determined Training on Cardiorespiratory Fitness in Recreationally Trained Females

Maintaining or increasing cardiorespiratory fitness (CRF) throughout a training season can be challenging for recreationally trained endurance athletes. Even if athletes intend to increase training during a training season, variables such as the total number of minutes they train per week (min·wk-1) and/or the min·wk-1 of moderate to high intensity training (MHIT) they participate in may affect these athletes’ ability to maintain or increase CRF. PURPOSE: The purpose of this study was twofold: 1) to examine changes in CRF over 8 weeks of self-determined training in recreational female endurance athletes who indicated they planned to increase training min·wk-1; and 2) to examine changes in minutes of total training and MHIT per week from self-reported exercise logs from weeks 1 and 8. METHODS: Fourteen recreationally trained female endurance athletes (cyclists (n=4) and runners (n=10)), all of whom had a baseline VO2max ≥ 80th percentile for their age, completed incremental running or cycling trials to exhaustion to determine VO2max, and provided 7 d exercise training logs at weeks 1 and 8. Runners completed incremental trials on a motorized treadmill, cyclists completed trials on an electronically braked cycle ergometer, and expired gases were measured with a metabolic system during all trials. To record training, athletes were instructed on the use of the Borg RPE scale (15-grade scale) to estimate exercise intensity (I), and were asked to record exercise min and I independently for all phases of exercise sessions. MHIT was considered to be any exercise I > an RPE of 13 (Somewhat Hard to Maximal Exertion on the Borg scale). RESULTS: There was no significant change in mean VO2max values in weeks 1 vs. 8 (p=0.062, 46.50 ± 3.68 vs. 45.87 ± 4.21 mL·kg-1·min-1). There was also no significant change in mean total training minutes (p=0.32, 601.8 ± 221.4 vs. 551.9 ± 194.2 min·wk-1) or mean total MHIT minutes (p=0.38, 272.5 ±193.3 vs. 334.5 ± 218.1 min·wk-1) in weeks 1 vs. 8. CONCLUSIONS: On average, CRF was maintained during the 8 weeks of self-determined recreational training. In addition, we found that average total training min and MHIT min did not change for this group in weeks 1 vs. 8, even though these recreational endurance athletes intended to increase their training during this 8-week period.

The effects of an unanticipated side-cut on lower extremity kinematics and ground reaction forces during a drop landing

Unanticipated direction to cut after landing may alter the lower extremity landing biomechanics when performing landing motions. These alterations may potentially increase the risk of ACL injury. The purpose of this study was to determine if an unanticipated side-cut affects lower extremity landing biomechanics in females. Eighteen recreational female athletes participated in two blocks of testing: the first block of testing consisted of three acceptable trials of anticipated dominant limb and non-dominant limb 45-degree diagonal cutting after landing, which were performed in a counterbalanced order. The second block of testing consisted of three acceptable trials of unanticipated dominant limb and non-dominant limb diagonal cutting after landing. Data analysis mainly focused on the dominant limb landing biomechanics. Unanticipated side-cut landing, compared (paired t-test, p < 0.05) to the anticipated landings, resulted in less hip abduction and tibial internal rotation angle at initial contact (IC) and a lower maximum ankle inversion angle and a greater maximum knee abduction angle, and knee and hip displacement. Also, greater posterior GRF and a longer time to peak medial GRF were exhibited. These outcomes indicate that athletes may adapt their landing mechanics to land unsafely when encountering an unanticipated event.

Effect of Fatigue on Lower Extremity Biomechanics during Repeated Vertical Jumps in College-Aged Females

Anterior cruciate ligament (ACL) injuries are common in females, and most non-contact ACL injuries occur during landing or cutting movements. Also, fatigue has been linked to an increased risk of injury. Accordingly, significantly more injuries occur during the latter portions of game performance, according to several epidemiological studies. However, a scarce amount of research exists regarding the effects of neuromuscular fatigue on landing biomechanics. We surmised that FL would cause abnormal lower extremity biomechanics. PURPOSE: To determine if a 60-second continuous bout of jumping affects lower extremity landing biomechanics in females. METHODS: Recreational female athletes (n=10; 63.9±6.5kg, 170.5±3.1cm) participated in this study. Participants performed established fatigue protocol: double leg vertical jumps every three seconds for 60 seconds. Participants were required to touch a suspended horizontal bar during each jump, with the bar height set by having participants hang from the bar and adjusting it until the height from the midpoint of the lateral malleolus to the ground was 0.4 m. The first three consecutive jumps from the first and last 10 seconds were chosen for data analysis. Reflective marker coordinates were reconstructed from locations captured from 7 cameras (240 Hz). Dominant-side lower extremity angular joint kinematics and ground reaction forces (GRF: 1,200 Hz) were compared between the non-fatigue landings (NFL) and fatigue landings (FL) using paired t-tests (p<.05). RESULTS: FL, compared to NFL, resulted in increased knee abduction angle (1.6±3.9° and 0.6±2.8°) and decreased knee flexion angle (2.7±5.2° and 4.0±6.3°) at initial contact (IC). An increased trunk maximum flexion angle (15.5±7.6° and 10.0±5.2°) and knee flexion displacement (58.7±12.8° and 55.6±13.6°) also occurred. Additionally, FL also resulted in a reduction in vertical GRF peak magnitude (1.47±0.24 N[BULLET OPERATOR]kg-1 and 1.75±0.26 N[BULLET OPERATOR]kg-1). CONCLUSION: At IC, both an extended knee position and greater knee abduction angle have been associated with an increase in ACL injury risk and loading. However, a decrease in peak vertical GRF and increased trunk flexion angle and knee flexion displacement are factors that decrease ACL injury risk and loading and may be adaptation strategies to protect the knee when fatigued.

Autologous Doping with Cryopreserved Red Blood Cells - Effects on Physical Performance and Detection by Multivariate Statistics.

The discovery of erythropoietin (EPO) simplified blood doping in sports, but improved detection methods, for EPO has forced cheating athletes to return to blood transfusion. Autologous blood transfusion with cryopreserved red blood cells (RBCs) is the method of choice, because no valid method exists to accurately detect such event. In endurance sports, it can be estimated that elite athletes improve performance by up to 3% with blood doping, regardless of method. Valid detection methods for autologous blood doping is important to maintain credibility of athletic performances. Recreational male (N = 27) and female (N = 11) athletes served as Transfusion (N = 28) and Control (N = 10) subjects in two different transfusion settings. Hematological variables and physical performance were measured before donation of 450 or 900 mL whole blood, and until four weeks after re-infusion of the cryopreserved RBC fraction. Blood was analyzed for transferrin, iron, Hb, EVF, MCV, MCHC, reticulocytes, leucocytes and EPO. Repeated measures multivariate analysis of variance (MANOVA) and pattern recognition using Principal Component Analysis (PCA) and Orthogonal Projections of Latent Structures (OPLS) discriminant analysis (DA) investigated differences between Control and Transfusion groups over time. Significant increase in performance (15 ± 8%) and VO2max (17 ± 10%) (mean ± SD) could be measured 48 h after RBC re-infusion, and remained increased for up to four weeks in some subjects. In total, 533 blood samples were included in the study (Clean = 220, Transfused = 313). In response to blood transfusion, the largest change in hematological variables occurred 48 h after blood donation, when Control and Transfused groups could be separated with OPLS-DA (R2 = 0.76/Q2 = 0.59). RBC re-infusion resulted in the best model (R2 = 0.40/Q2 = 0.10) at the first sampling point (48 h), predicting one false positive and one false negative. Over all, a 25% and 86% false positives ratio was achieved in two separate trials. In conclusions, autologous re-infusion of RBCs increased VO2max and performance as hypothesized, but hematological profiling by multivariate statistics could not reach the WADA stipulated false positive ratio of <0.001% at any time point investigated. A majority of samples remained within limits of normal individual variation at all times.

Effect of Limb Dominance on Landing Biomechanics Prior to a Cutting Movement.

Non-contact anterior cruciate ligament (ACL) injuries are common in females, and a majority of these injuries occur during the landing phase after being airborne. Several epidemiological studies have been reported that limb dominance is a possible etiological factor for noncontact ACL injuries. However, the findings of these investigations are conflicting. Asymmetry of lower extremity landing mechanics between limbs before cutting may provide a better understanding of the relationship between limb dominance and non-contact ACL injury risk. PURPOSE: To determine if limb dominance affects lower extremity landing biomechanics in females before cuttings. METHODS: Recreational female athletes (n = 17; 21.2±1.5 yr, 63.3±4.8 kg, 169.1±4.0 cm) participated in this study. Participants performed double leg drop landings (ht = .5m) with each foot landing onto a separate force platform (1200 Hz). After landing, participants performed a 45° diagonal cut. Participants performed 3 trials for each cut direction. The participant’s trials were classified by the limb that was used to push off the ground to make the cut: dominant (DC) and non-dominant (NDC). Reflective marker coordinates were reconstructed from locations captured from 7 motion-capture cameras (240 Hz). Lower extremity angular joint kinematics and ground reaction forces (GRF) were compared between the cutting conditions using paired t-tests (p<.05). RESULTS: DC compared to NDC resulted in decreased knee flexion (44.9±6.4° and 50.4±5.5°), increased ankle inversion (10.6.±4.0° and 6.0±5.2°), and significant difference hip abduction-adduction (0.7±3.1° and -3.2±3.4°) displacements; and greater maximum ankle inversion (13.6±5.6° and 6.3±7.9°) angle. No GRF differences were detected. CONCLUSION: During a landing prior to cutting movement, DC’s lower knee flexion displacement occur to help maintain a more upright posture, increasing stability, but could potentially increase ACL loading, and may lead to less knee extension during push-off, and require increased ankle inversion displacements in compensation. Furthermore, hip adduction displacement and increased ankle inversion displacements possibly lead malalignment for the frontal plane joint kinematics which surmised to be involved in ACL landing injuries.