Female Recreational Athletes Research Articles

Effect Of Sex And Neuromuscular Training On Lower Limb Stiffness Characteristics And Jump Performance

Stiffness is potentially related to sports injury and athletic performance. Higher stiffness within a certain range may represent lower sports injury risk and better athletic performance. It is not clear whether a sex difference existed in lower limb stiffness changes induced by neuromuscular training. PURPOSE: To investigate the effect of neuromuscular training on lower limb stiffness in both male and female young recreational athletes. METHODS: Eleven recreational athletes (5 females: 24.4 ± 3.4 yr; 6 males: 24.0 ± 3.9 yr) underwent neuromuscular training 3 times a week for continuous 6 weeks, including plyometric training (e.g. squat jump, wall jump et al.) and strength training (e.g. barbell squat, bench press et al.) with progression every two weeks. Pre- and post-intervention measurements included: gastrocnemius lateralis (GL), gastrocnemius medialis (GM), soleus muscle and the Achilles tendon (AT) stiffness on both lower limbs by Myometer; vertical stiffness (Kvert), jump height and reactive strength index (RSI) by force plate during drop vertical jump from a 40 cm step. RESULTS: Two-way repeated measures ANOVA was conducted and found no significant interaction between time and sex in all the variables mentioned above, but significant results on time in left GL stiffness (p=0.021), left GM stiffness (p=0.008), right AT stiffness (p=0.040), Kvert (p=0.019), jump height (p=0.012), and RSI (p=0.008). Paired-T test was further conducted and identified jump height in females increased significantly from pre (0.14 ± 0.04 m) to post (0.18 ± 0.05 m) intervention (p=0.037). After intervention, left GL stiffness had a downward tendency in males (Δ=39.69 ± 68.24 N/m) and females (Δ=70.00 ± 60.46 N/m); left GM stiffness tended to increase in males (Δ=34.17 ± 82.22 N/m) and decrease in females (Δ=29.60 ± 63.53 N/m); right AT stiffness (Δ=52.17 ± 215.48 N/m) and Kvert (Δ=199.33 ± 207.36 N/m) tended to decrease in males; RSI in males (Δ=0.16 ± 0.15 m/s) and females (Δ=0.162 ± 0.146 m/s) tended to increase. CONCLUSIONS: Males and females may achieve similar benefits from neuromuscular training. Neuromuscular training can improve jump performance in females, with a tendency to decrease lower limb stiffness in males and females. Supported by Shanghai University of Sports A1-3G02-19-000209

Examination Of Energy Needs Across 2-week High-Intense Functional Exercise Program In Recreational Athletes

Increases in physical activity without proper nutritional knowledge may expose recreational athletes to compromised energy needs and macronutrient profiles. PURPOSE: To examine the energy needs across a 2-week high intense functional exercise program in female and male recreational athletes. METHODS: Thirty adults (age: 31.2 ± 8.1; females: 164.7 ± 7.1 cm, 69.9 ± 11.1 kg; body fat%: 29.2 ± 5.5%; males: n=12, 176.9 ± 6.2 cm, 89.5 ± 15.1 kg, body fat%: 22.3 ± 8.8%) participated in a larger cross-sectional study. Participants completed a demographic survey, a 7 day online dietary and exercise log across 2 weeks. Measurements included; height, weight, and DXA scan (body fat%) at the beginning of the study. Exercise energy expenditure (EEE) was calculated using Ainsworth/Heyward equations, energy availability (EA) was calculated by EA = ((EI - EEE)/FFM.kg-1) and energy balance (EB) was calculated by EB = (EI – TDEE = 0). Macronutrients (CHO, PRO, and fats) were assessed using ACSM recommendations (recs.). Low EA (LEA) was defined at >30 kcals/FFM.kg-1 and EB was defined as negative, balanced, or positive, and Macros were defined as low, within or above recs. RESULTS: Results yielded LEA (week 1: 73.3%, n = 22, week 2: 80% n=24) and negative EB (week 1: 94.4%, n=17; 75.0%, n=9) across the two weeks. No significant differences were found between gender or training weeks for energy needs and Macros. Over the 2 weeks, participants demonstrated similar energy needs including: EI (week 1: 1752.3 ± 599.8 kcals, week 2: 1831.2 ± 634.4 kcals), EEE (week 1: 310.7 ± 63.7 kcals, week 2:302.7 ± 62.1 kcals), EA: (week 1: 25 ± 10.1 kcals/FFM.kg-1, week 2: 25.1 ± 9.8 kcals/FFM.kg-1), TDEE (week 1: 2518.5 ± 266.1 kcals, week 2: 2543.1 ± 286.1 kcals), and EB (week 1: -766.2 ± 627.4 kcals, week 2: -712 ± 652.3 kcals). Macronutrients were also similar between weeks; with PRO intake within recommendations (week 1: 50%, n=15; week 2: 63%, n=17, n=6), CHO intake was extremely low (week 1: 96.7%, n=29; week 2: 93.3%, n=28,) and fats were within recs. (week 1: 62.1%, n=18; week 2: 46.7%, n=9). CONCLUSION: Participants demonstrated consistent EI and EEE habits over the 2 weeks, however, the recreational athletes under consumed CHO and presented at risk for LEA and negative EB. This leads to compromised fueling for the EEE utilized during training. Funded by Avadim Technology

Relationship Between Neurocognition Level and Neuromuscular Strategy During Landing in Female Recreational Athletes

If judgment errors regarding ground conditions or fall height occur in the feedforward control process, players can be exposed to the risk of musculoskeletal injury to the lower extremity. This study aimed to investigate the effects of neurocognition level on neuromuscular strategy during landing in female recreational soccer players. Ten female recreational soccer players (age: 21.2 ± 3.4 years, height: 163.8 ± 3.8 cm, body mass: 57.0 ± 8.3 kg) participated in this study. Neurocognition levels were analyzed using the Central Nervous System Vital Signs test, and the muscle activation patterns, angles of the agonist lower extremity, and vertical ground reaction force were analyzed. A Pearson correlation analysis was used to identify the relationship between neurocognition and neuromuscular landing strategy. The results indicate that the neurocognition level correlates with muscle activation and kinematics of the lower extremity. We found a clear correlation between neurocognition scores and integral muscle activation as well as the kinematics of the lower extremity. Moreover, we found that higher neurocognition scores corresponded to an improved neuromuscular landing strategy in regard to deceleration, increased knee stability, and improved shock absorption during landing.

Relationship Between Neurocognition Level and Neuromuscular Strategy During Landing in Female Recreational Athletes

Relationship Between Neurocognition Level and Neuromuscular Strategy During Landing in Female Recreational Athletes

Relationship Between Neurocognition Level and Neuromuscular Strategy During Landing in Female Recreational Athletes

Relationship Between Neurocognition Level and Neuromuscular Strategy During Landing in Female Recreational Athletes

Concurrent Validity and Reliability of My Jump 2 App for Measuring Vertical Jump Height in Recreationally Active Adults

This study aimed to examine the reliability, validity, and usefulness of the smartphone-based application, My Jump 2, against Optojump in recreationally active adults. Participants (18 women, 28.9 ± 5.6 years, and 26 men, 30.1 ± 10.6 years) completed squat jumps (SJ), counter-movement jumps (CMJ), and CMJ with arm swing (CMJAS) on Optojump and were simultaneously recorded using My Jump 2. To evaluate concurrent validity, jump height, calculated from flight time attained from each device, was compared for each jump type. Test-retest reliability was determined by replicating data analysis of My Jump 2 recordings on two occasions separated by two weeks. High test-retest reliability (Intraclass correlation coefficient (ICC) > 0.93) was observed for all measures in both male and female athletes. Very large correlations were observed between the My Jump 2 app and Optojump for SJ (r = 0.95, p = 0.001), CMJ (r = 0.98, p = 0.001), and CMJAS (r = 0.98, p = 0.001) in male athletes. Similar results were obtained for female recreational athletes for all jumps (r > 0.94, p = 0.001). The study results suggest that My Jump 2 is a valid, reliable, and useful tool for measuring vertical jump in recreationally active adults. Therefore, due to its simplicity and practicality, it can be used by practitioners, coaches, and recreationally-active adults to measure vertical jump performance with a simple test as SJ, CMJ, and CMJAS.

The risk of low energy availability in Chinese elite and recreational female aesthetic sports athletes

BackgroundLow energy availability (LEA) is a medical condition observed in athletes, with a higher prevalence in aesthetic sports. For the first time, this study evaluated the relative prevalence of LEA in female elite athletes (ELA) and recreational athletes (REA) in aesthetic sports in China.MethodsFemale athletes from 6 sports (trampolining, rhythmic gymnastics, aerobics, dance sport, cheerleading and dance) were recruited, including ELA (n = 52; age = 20 ± 3) on Chinese national teams and REA (n = 114; Age = 20 ± 2) from Beijing Sport University. Participants completed 2 online questionnaires to assess LEA and eating disorder risk. These included the Low Energy Availability in Females Questionnaire (LEAF-Q), which provided information on injury history, gastrointestinal function and menstrual history, and the Eating Disorder Inventory-3 Referral Form (EDI-3 RF). For a sub-group of elite athletes (n = 14), body composition, bone mineral density, and blood serum were also quantified.ResultsA total of 41.6% of participants (n = 69) were at increased risk of LEA, and 57.2% of participants (n = 95) were classified as high in eating disorder risk. For ELA vs. REA, there was a significantly higher prevalence of LEA risk (55.8% vs. 35.1%; p = 0.012) and amenorrhea (53.8% vs. 13.3%; p < 0.001). Elite athletes at increased risk of LEA had significantly lower estradiol (p = 0.021) and whole-body BMD (p = 0.028). Pearson correlations indicated that the whole-body BMD (r = − 0.667, p = 0.009) correlated negatively with LEAF-Q score.ConclusionsResults of this study indicate that there is a risk of LEA in female Chinese athletes within aesthetic sports, and significantly higher prevalence of increased LEA risk observed in ELA than in REA. Chinese coaches and sports medicine staff working elite female athletes in aesthetic sports should develop strategies to reduce the prevalence of LEA.

Difference in leg asymmetry between female collegiate athletes and recreational athletes during drop vertical jump

BackgroundNeuromuscular imbalance will lead to loading asymmetry in sporting activities. This asymmetry is related to leg dominance, which has been associated with increased risk of anterior cruciate ligament (ACL) injury. Therefore, potential biomechanical differences between legs are important. However, little attention has been paid to the biomechanical details of leg dominance. The purpose of the present study was to clarify the relationship between leg dominance and knee biomechanics in females with different activity level during dynamic athletic tasks.MethodsA total of 23 female collegiate (mean age = 19.6 ± 1.4 years, mean body mass index = 21.5 ± 0.9) and 19 recreational athletes (mean age = 20.7 ± 1.1 years, mean body mass index = 20.5 ± 1.7) were enrolled. Tegner activity scores of the collegiate and recreational athletes were 9 and 7, respectively. Knee kinematic and kinetic asymmetries between the dominant (DL) and non-dominant (NDL) legs during the landing phase of drop vertical jump (DVJ) were assessed using three-dimensional motion analysis in collegiate and recreational athletes separately. Statistical comparison was done using two-tailed paired t test between DL and NDL in each athlete.ResultsThe peak knee abduction angle was significantly larger on the DL than on the NDL in collegiate athletes. Knee abduction angle at initial contact (IC), peak knee abduction angle, knee internal rotation angle at IC, and peak knee internal rotation angle were significantly larger on the NDL than on the DL in recreational athletes. Moreover, peak knee abduction moment within 40 ms from IC was larger on the NDL than on the DL in recreational athletes, while the moment was not significantly different in collegiate athletes.ConclusionsFrom the present study, the relationship between leg dominance and knee biomechanics was totally different in females with different activity level. Specifically, asymmetry of the knee abduction angle between limbs was opposite between female recreational and collegiate athletes. According to previous literatures, abduction and internal rotation angles as well as abduction moment were key issues for mechanism of non-contact ACL injury. Therefore, the NDL in female recreational athletes was associated with increased risk of ACL injury.

Examination of Low Energy Availability and Macronutrient Intake among Male and Female Recreational Athletes

Examination of Low Energy Availability and Macronutrient Intake among Male and Female Recreational Athletes

The Effect Of Cold-water Immersion On Joint Power During Drop-landings

Exposure to cold environments results in pronounced alterations in many physiological systems. Military exercises, recreational situations, and popular winter sports could introduce large changes in tissue temperatures of the lower body. To date, the effect of cold exposure on joint mechanics during high impact activities (e.g. drop-landings) remains unknown. It is unclear whether cold exposure could reduce joints’ ability to absorb landing impact, which may increase risks of landing related injuries. PURPOSE: To determine the effect of cold-water immersion on lower-extremity joint power during drop-landings. METHODS: On four separate occasions, 11 female recreational athletes (22±2 yr, 65±7 kg, 1.67±0.06 m) performed drop-landings (single-leg and double-leg landings) from a 0.6-m height following 30-minute immersion in thermoneutral water (CON) (34 °C) to the hip-joint level and in cold-water (20 °C) to the ankle- (LOW), knee- (MED), and hip- (HIGH) joint levels. 3D motion capture was conducted. Lower-extremity joint power was calculated. One way repeated measures ANOVA was used to determine differences among the four conditions. RESULTS: No significant differences in peak power absorption among all testing conditions for either the single-leg landing (p>0.05) or double-leg landing (p>0.05). For single-leg landing, the mean±SD of the power absorption (W/kg) during water-immersions (CON, LOW, MED, and HIGH) were 22.1±3.4, 21.9±2.9, 22.0±3.1, 22.8±3.1, for the ankle, respectively, and 34.7±7.1, 34.4±6.3, 33.3±6.2, 34.4±7.5, for the knee, respectively, and 39.1±8.9, 39.9±11.3, 38.4±5.1, 39.5±8.3, for the hip, respectively. For double-leg landing, the power absorption during water-immersions (CON, LOW, MED, and HIGH) were 18.7±2.9, 19.2±2.8, 18.8±1.9, 18.6±2.8, for the ankle, respectively, and 32.6±6.0, 32.5±5.6, 31.5±4.0, 33.3±7.4, for the knee, respectively, and 33.3±14.1, 31.9±16.6, 29.9±12.8, 31.8±16.0, for the hip, respectively. CONCLUSION: For recreational athletes, drop-landing engages sub-maximal eccentric effort at leg’s muscle-tendon units to absorb impact. Although cold-water lowers tissue temperature, the ability of lower-extremity joints to absorb landing impact remains intact. Thus, the risk of landing related injuries may not be elevated due to cold exposure.

The Influence of Ankle Braces on Functional Performance Tests and Ankle Joint Range of Motion.

The lateral ankle sprain is one of the most common lower-extremity injuries in sports. Previous research has found that some prophylactic ankle supports reduce the risk of recurrent ankle sprains and provide extra support to the joint. However, there is a continued concern that these supports may negatively influence performance. To determine if wearing an ankle brace influences athlete performance and ankle kinematics during functional performance tests. Repeated measures. University gymnasium. Male and female recreational or competitive athletes (n = 20). Participants performed 3 trials of a standing long jump, vertical jump, 40-yard sprint, and T-drill under each of the following 3 conditions: wearing traditional lace-up brace (brace 1), modified lace-up brace (brace 2), and no-brace. A 2-dimensional motion capture camera was used to measure ankle range of motion (ROM) in the sagittal plane during the vertical and standing long jumps and in the frontal plane during the cutting phase of the T-drill. Performance of each test and ankle ROM were compared between each of the braced conditions. Ankle braces did not influence performance in speed or agility functional performance tests (P > .05). Ankle braces negatively affected performance of the standing long jump (P = .01) and vertical jump (P = .01). There was no significant difference between brace or no-brace conditions in ankle inversion ROM during the T-drill (P > .05). Both brace conditions restricted ROM in the sagittal plane during the vertical and standing long jumps (P < .05). Braced conditions restricted sagittal plane ROM during the vertical jump and long jump. This decrease in ROM explains the decline in functional performance also seen during these tests.

The combined impact of a perceptual–cognitive task and neuromuscular fatigue on knee biomechanics during landing

BackgroundA large majority of anterior cruciate ligament (ACL) injuries are non-contact, most often occurring during a landing or change of direction. Recent research indicates that cognitive factors may be involved in non-contact ACL injuries. The aim of this study was to determine if a game-situation perceptual–cognitive load leads to altered landing kinematics in physically fatigued female athletes. MethodsNineteen female recreational athletes were recruited to perform a series of jumping and landing trials. In a first phase, eight trials were performed in an isolated condition and eight were performed while participants performed a perceptual–cognitive task. Before a second identical phase, participants underwent a muscular fatigue protocol. Knee-joint kinematics were recorded and compared between conditions using paired t-tests. ResultsMuscle fatigue led to statistically significant increases in peak knee abduction and peak internal knee rotation as well as a decrease in maximum knee flexion, when comparing conditions without the perceptual–cognitive task. The perceptual–cognitive task had no statistically significant effect on any knee rotations, either pre- or post-fatigue. However, a subgroup of 12 athletes showed a significant increase in knee abduction in the presence of the perceptual–cognitive task, only in the fatigued condition. ConclusionA perceptual–cognitive task combined with muscle fatigue alters knee kinematics of landing for a subset of recreational athletes, potentially increasing the risk of ACL rupture. Further studies are necessary to confirm this finding and to identify characteristics of at-risk individuals to target them for injury prevention protocols.

Association Between the 25-Hydroxyvitamin D Status and Physical Performance in Healthy Recreational Athletes.

Molecular and clinical studies have linked vitamin D (vitD) deficiency to several aspects of muscle performance. For this retrospective cross-sectional study data from 297 male (M) and 284 female (F) healthy recreational athletes were used to evaluate the prevalence of vitD deficiency in athletes living in Austria and to determine whether serum 25-hydroxyvitamin D (25(OH)D) correlates with maximal (Pmax) and submaximal physical performance (Psubmax) measured on a treadmill ergometer. The data were controlled for age, season, weekly training hours (WTH), body mass index (BMI) and smoking status. 96 M and 75 F had 25(OH)D levels ≤ 20 ng/mL. 25(OH)D levels showed seasonal variations, but no seasonal differences in Pmax and Psubmax were detected. M with 25(OH)D levels ≤ 20 ng/mL had significantly lower Psubmax (p = 0.045) than those with normal levels. In F no significant differences in Pmax or Psubmax were detected. Stepwise multiple regression analysis including all covariates revealed significant correlations between 25(OH)D levels and Pmax (β = 0.138, p = 0.003) and Psubmax (β = 0.152, p = 0.002) in M. Interestingly, for F significant correlations between 25(OH)D and both Pmax and Psubmax disappeared after adding WTH to the model. In conclusion, our data suggest that 25(OH)D status is associated with physical performance especially in M, while in F, WTH and BMI seem to affect the correlation.

Vertical drop jump landing depth influences knee kinematics in female recreational athletes

ObjectivesTo examine whether different vertical drop jump (VDJ) landing depth (small versus deep) and stance width (wide versus narrow) may alter movement biomechanics in female recreational athletes. The purpose was also to identify whether leg muscle strength is a predictive factor for knee control during a VDJ. DesignCross-sectional. SettingBiomechanics laboratory. Participants: Eighteen women aged between 18 and 30 years. Main outcome measuresThree VDJ tests were used for biomechanical analysis: 1) small “bounce” jump (BJ), 2) deep “countermovement” jump with wide (CMJW) and 3) narrow foot position (CMJN). Subjects also performed an isometric knee-extension strength test, dichotomized to ‘weak’ versus ‘strong’ subjects according to median and quartiles. ResultsThere were greater knee valgus angles during landing for both the CMJW and CMJN test compared to the BJ test (p ≤ 0.05). Differences in knee valgus between weak and strong subjects were significant for the BJ test (p = 0.044) but not for any of the other tests. ConclusionsVDJ landing depth influences knee kinematics in women. Landing depth may therefore be considered when screening athletes using the VDJ test. Also, muscle strength seems to influence the amount of knee valgus angles, but the difference was not statistically significant (except for the BJ test) in this small cohort.

The validity and reliability of the GymAware linear position transducer for measuring counter-movement jump performance in female athletes

ABSTRACTThe current study aimed to assess the validity and test–retest reliability of a linear position transducer when compared to a force plate through a counter-movement jump in female participants. Twenty-seven female recreational athletes (19 ± 2 years) performed three counter-movement jumps simultaneously using the linear position transducer and force plate for validity. In addition, 11 elite female athletes (23 ± 6 years) performed 3 counter-movement jumps with the linear position transducer on three separate days for test–retest reliability. Pearson correlations for jump height between the devices were at a high level (r = .90), with the linear position transducer overestimating jump height by 7.0 ± 2.8 cm. The reliability measured by the linear position transducer resulted in a mean intraclass correlation of .70 for jump height, .90 for peak velocity, and .91 for mean velocity. The linear position transducer was reliable for measuring counter-movement jumps in elite female athletes; however, caution should be taken for one-off jump measures as it may over-estimate jump height.

Sedentary Time in Male and Female Masters and Recreational Athletes Aged 55 and Older

The purpose of this study was to quantify sedentary time among recreational and Masters (competitive) athletes aged 55 and older. A cross-sectional survey including questions on demographics, sport participation, as well as a short form of the International Physical Activity Questionnaire, and the Measure of Older Adult's Sedentary Time questionnaire was administered (n = 203). Male Masters athletes reported more time spent in vigorous intensity physical activity and less time watching TV than recreational athletes. Among females, being a Masters athlete was associated with being more sedentary than being a recreational athlete, while among males, being a recreational athlete was associated with being more sedentary. The intensity and duration that older Masters and recreational athletes spent in their sport was inversely associated with the amount of sedentary time accumulated. Future research using inclinometers is needed to further elucidate sedentary time in older male and female athletes.

Influence of two-month training program on anthropometry and VO2max in recreational athletes

The aim was to evaluate the effect of a two-month training program on some anthropometric characteristics and maximum oxygen consumption (VO2 max) in male and female recreational athletes. Study included 62 participants, 30 males and 32 females. All participants were doing recreational sport, aged from 35 to 50 years old. In order to obtain accurate results, the following instruments were used: measuring tape, InnerScan body composition monitor Tanita BC-532, and "Technogym" treadmill where they were performing submaximal aerobic test. Training process lasted for two months and consisted of two testing sessions. The training program has included three sessions per week for about 90 minutes. T-test for paired samples was used in the statistical program "SPSS", and results suggested that there was a positive effect of a two-month training process on certain anthropometric characteristics and the maximal oxygen uptake in both male and female subjects.

High- compared to low-arched athletes exhibit smaller knee abduction moments in walking and running

High- (HA) and low-arched athletes (LA) experience distinct injury patterns. These injuries are the result of the interaction of structure and biomechanics. A suggested mechanism of patellofemoral pain pertains to frontal plane knee moments which may be exaggerated in LA athletes. We hypothesize that LA athletes will exhibit greater peak knee abduction moments than high-arched athletes. MethodsTwenty healthy female recreational athletes (10HA and 10LA) performed five over-ground barefoot walking and five barefoot running trials at a self-selected velocity while three-dimensional kinematics and ground reaction forces were recorded. Peak knee abduction moments and time-to-peak knee abduction moments were calculated using Visual 3D. ResultsHigh-arched athletes had smaller peak knee abduction moments compared to low-arched athletes during walking (KAM1: p=0.019; KAM2: p=0.015) and running (p=0.010). No differences were observed in time-to-peak knee abduction moment during walking (KAM1: p=0.360; KAM2: p=0.085) or running (p=0.359). ConclusionsThese findings demonstrate that foot type is associated with altered frontal plane knee kinetics which may contribute to patellofemoral pain. Future research should address the efficacy of clinical interventions including orthotics and rehabilitation programs in these athletes.

Effect of sex and fatigue on muscle stiffness and musculoarticular stiffness of the knee joint in a young active population

ABSTRACTThe purpose of this study was to investigate the influence of sex and fatigue on knee extensor peak torque (PT), muscle stiffness (MS) of the vastus lateralis (VL) and knee joint musculoarticular stiffness (MAS) in young adults. Twenty-two male and 22 female recreational athletes participated. Males were characterised by higher relaxed [pre-: males 364.43 (52.00) N · m–1, females 270.27 (37.25) N · m–1; post-: males 446.75 (83.27) N · m–1, females 307.39 (38.58) N · m–1] and contracted [pre-: males 495.07 (71.04) N · m–1, females 332.34 (85.42) N · m–1; post-: males 546.37 (90.74) N · m–1, females 349.21 (85.55) N · m–1] MS of the VL, and knee joint MAS [pre-: males 1450.11 (507.98) N · m–1, females 1027.99 (227.33) N · m–1; post-: males 1345.81 (404.90) N · m–1, females 952.78 (192.38) N · m–1] than females pre- and post-fatigue. A similar finding was observed in pre-fatigue normalised knee extensor PT [pre-: males 2.77 (0.42) N · m kg–1, females 2.41 (0.40) N · m kg–1, post-: males 2.53 (0.54) N · m kg–1, females 2.26 (0.44) N · m kg–1]. After the fatigue protocol, normalised knee extensor PT and knee joint MAS decreased, whilst relaxed and contracted MS of the VL increased in both sexes. These observed differences may contribute to the higher risk of knee injury in females and following the onset of fatigue.

Arch structure is associated with unique joint work, relative joint contributions and stiffness during landing

To examine lower extremity joint contributions to a landing task in high-(HA) and low-arched (LA) female athletes by quantifying vertical stiffness, joint work and relative joint contributions to landing. MethodsTwenty healthy female recreational athletes (10 HA and 10 LA) performed five barefoot drop landings from a height of 30cm. Three-dimensional kinematics (240Hz) and ground reaction forces (960Hz) were recorded simultaneously. Vertical stiffness, joint work values and relative joint work values were calculated using Visual 3D and MatLab. ResultsHA athletes had significantly greater vertical stiffness compared to LA athletes (p=0.013). Though no differences in ankle joint work were observed (p=0.252), HA athletes had smaller magnitudes of knee (p=0.046), hip (p=0.019) and total lower extremity joint work values (p=0.016) compared to LA athletes. HA athletes had greater relative contributions of the ankle (p=0.032) and smaller relative contributions of the hip (p=0.049) compared to LA athletes. No differences in relative contributions of the knee were observed (p=0.255). ConclusionsThese findings demonstrate that aberrant foot structure is associated with unique contributions of lower extremity joints to load attenuation during landing. These data may provide insight into the unique injury mechanisms associated with arch height in female athletes.