Gender differences in limb and joint stiffness during the fencing lunge

The aim of the current investigation was to examine gender differences in limb and joint stiffness characteristics during the fencing lunge. Ten male and ten female fencers completed simulated lunge movements. Lower limb kinematics were collected using an eight camera optoelectric motion capture system which operated at 250 Hz. Measures of limb and joint stiffness were calculated as a function of limb length and joint moments divided by the extent of limb and joint excursion. Gender differences in limb joint stiffness parameters were examined statistically using independent samples t-tests. The results showed firstly that both limb (male = 64.22 ±19.12, female = 75.09 ±22.15 N.kg.m) and hip stiffness (male = 10.50 ±6.00, female = 25.89 ±15.01 Nm.kg.rad) were significantly greater in female fencers. In addition it was also demonstrated that knee moment (male = 1.64 ±0.23, female = 2.00 ±0.75 Nm.kg) was significantly larger in females. On the basis of these observations, the findings from the current investigation may provide further insight into the aetiology of the distinct injury patterns observed between genders in relation to fencing

Barefoot and shod running: their effects on foot muscle kinetics

Running shoe technology has advanced significantly in the last 50 years, although the overall injury rate has yet to decrease. Barefoot (BF) running has become increasing more popular in the last 10 years. The current investigation aimed to explore differences in the forces produced by the foot muscles during BF and shod (SH) running. Fifteen male participants ran at 4.0 m.s-1 (± 5%). Kinematics were measured using an eight-camera motion analysis system alongside ground reaction forces. Peak and average stance phase forces from the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus (PL), extensor digitorum longus (EDL) and extensor hallucis longus (EHL) muscles were obtained using OpenSim v3.2. Peak and average forces of the FDL, FHL and PL muscles were significantly larger when running BF, whereas peak and average forces of the FHL and EHL muscles were significantly larger when running SH. This study supports the conjecture that the plantar muscles are required to work harder when running BF in relation to SH, indicating that BF training may serve to strengthen the foot musculature

Side to side differences in hamstring muscle kinematics during maximal instep soccer kicking

Hamstring strains are a common non-contact injury in soccer. The current study investigates bilateral differences in hamstring kinematics during maximal instep kicking. Thirteen male soccer players performed maximal instep kicks with their dominant and non-dominant limbs. Muscle-tendon kinematics of the four hamstring muscles during the kick movement were quantified using OpenSim software. Differences between dominant and non-dominant limbs were examined using paired t-tests. The results revealed that the biceps femoris long head (dominant = 165.28. ± 62.46 & non-dominant = 137.65 ± 52.17%), semimembranosus (dominant = 220.75 ± 43.35 & non-dominant = 131.23 ± 36.74%) and semitendinosus (dominant = 90.95 ± 16.69% and non-dominant = 80.47 ± 15.99%) experienced significantly greater strain when using the dominant limb. The current investigation provides key information regarding the mechanics of the hamstring group during maximal instep kicking, indicating that kicking with the dominant limb may place soccer players at increased risk from hamstring strain injury

Sex variation in patellar tendon kinetics during running

Purpose. The aim of the current investigation was to determine whether female recreational runners exhibit distinct patellar tendon loading patterns in relation to their male counterparts. Methods. Twelve male (age 26.55 ± 4.11 years, height 1.78 ± 0.11 m, mass 77.11 ± 5.06 kg) and twelve female (age 26.67 ± 5.34 years, height 1.67 ± 0.12 m, mass 63.28 ± 9.75 kg) runners ran over a force platform at 4.0 m · s –1. Lower limb kinematics were collected using an eight-camera optoelectric motion capture system which operated at 250 Hz. Patellar tendon loads were examined using a predictive algorithm. Sex differences in limb, knee and ankle joint stiffness were examined statistically using independent samples t tests. Results. The results indicate that patellar tendon force (male = 6.49 ± 2.28, female = 7.03 ± 1.35) and patelllar tendon loading rate (male = 92.41 ± 32.51, female = 111.05 ± 48.58) were significantly higher in female runners. Conclusions. Excessive tendon loading in female runners indicates that female runners may be at increased risk of patellar tendon pathologies

The influence of barefoot and shod running on Triceps-surae muscle strain characteristics

The aim of the current investigation was to determine the effects of barefoot and shod running on the kinematics of the Triceps-Surae muscle group. Twelve male participants ran at 4.0 m.s-1 (± 5%) in both barefoot and shod conditions. Kinematics were measured using an eight-camera motion analysis system. Muscle kinematics from the lateral Gastrocnemius, medial Gastrocnemius and Soleus were obtained using musculoskeletal modelling software (Opensim v3.2). The results showed that muscle strain for the lateral Gastrocnemius (barefoot = 1.10 & shod = 0.33 %), medial Gastrocnemius (barefoot = 1.07 & shod = 0.32 %) and Soleus (barefoot = 3.43 & shod = 2.18 %) were significantly larger for the barefoot condition. Given the proposed association between the extent of muscle strain and the etiology of chronic muscle strain pathologies, the current investigation shows that running barefoot may place runners at greater risk from Triceps-Surae strain injuries

Multi-segment foot kinematics and plantar fascia strain during treadmill and overground running

Although physiologically beneficial, running is known to be associated with a high incidence of chronic injuries. Excessive coronal and transverse plane motions of the foot segments and strain experienced by the plantar fascia are linked to the development of a number of chronic injuries. This study examined differences in multi-segment foot kinematics and plantar fascia strain during treadmill and overground running. Twelve male recreational runners ran at 4.0 m.s-1 in both treadmill and overground conditions. Multi-segment foot kinematics and plantar fascia strain were measured using an eight-camera motion analysis system and contrasted using paired samples t-tests. The results showed that plantar fascia strain was significantly greater in the overground condition (8.23 ± 2.77) compared to the treadmill (5.53 ± 2.25). Given the proposed relationship between excessive plantar fascia strain and the etiology of injury, overground running may be associated with a higher incidence of injury although further work is necessary before causation can be confirmed

Effects of new military footwear on knee loading during running

Military recruits are known to be susceptible to chronic injuries. The knee is the most common injury site and patellofemoral pain has been demonstrated as the leading mechanism for medical military discharge. Military boots have been cited as a key mechanism responsible for the high incidence of chronic injuries. The British Army has therefore introduced two new footwears – a cross-trainer and running shoe to reduce the incidence of chronic injuries. The aim of this study was to compare knee joint kinetics of the cross-trainer and running shoe in relation to conventional military boots. Twelve male participants ran at 4.0 m s−1 in each footwear condition. Knee joint kinetics was obtained and contrasted using repeated-measures ANOVAs. The results showed that patellofemoral load was significantly greater in the military boots. However, peak knee abduction moment was significantly greater in the running shoes. On the basis of the findings from this study, it is recommended that recruits who are susceptible to injuries mediated through excessive knee loads select the cross-trainer for their running activities

A re-appraisal of the fertility response to the Australian baby bonus

The Australian baby bonus offering parents $3,000 on the birth of a new child was announced on May 11 2004. The availability of five years of birth data following the introduction of the baby bonus allows for a more comprehensive analysis of the policy implications than is current in the literature. The focus of this paper is to identify if there is a positive fertility choice response to the introduction of the Australian baby bonus policy and if this response is sustained over time. To do this 19 years of birth and macroeconomic data, beginning 1990, is analysed using an unobservable components model. The results indicate a significant increase in birth numbers ten months following the announcement of the baby bonus, and this overall increase was sustained up to the end of the observed period. A cumulative growth in birth numbers which commenced in January 2006 slows in 2008 and 2009. It is suggested that the initial increase in births, identified in March 2005, is a direct fertility response to the introduction of the policy and that the subsequent change in the growth of birth numbers may be the result of a delayed effect working through a number of channels. It is estimated that approximately 119,000 births are attributable to the baby bonus over the period, at an approximate cost of$39000 per extra child.Fertility Rate, Time Series, baby bonus

Gender differences in multi-segment foot kinematics and plantar fascia strain during running

This study aimed to determine whether there are gender differences in multi-segment foot kinematics and plantar fascia strain during running. Fifteen male and fifteen female participants ran at 4.0- m.s-1. Multi-segment foot kinematics and plantar fascia strain were quantified using a motion capture system and compared between genders using independent samples t-tests. The results showed that plantar fascia strain was significantly greater in males (0.09 ± 0.04) compared to females (0.06 ± 0.03). Furthermore male runners (-9.72 ± 3.09) were also associated with a significantly larger peak calcaneal eversion angle compared to females (-6.03 ± 2.33). Given the proposed relationship between high levels of plantar fascia strain as well as excessive coronal plane rotations of the foot segments and the etiology of injury, it is likely that the potential risk of the developing running injuries in relation to these mechanisms is higher in males