The measurement of kinetic variables in race walking

The purpose of this study was to measure kinetic variables during race walking. Forty national and international race walkers walked either 5 km or 10 km at a pace equivalent to 105% of their season’s best time. Junior athletes walked 5 km, while senior athletes (mostly 20 km walkers) walked 10 km. Kinetic data were collected using a Gaitway treadmill (1000 Hz). Data were collected at the 2.5 km point. Men had longer step lengths than women and walked faster as a result. There was little difference in cadence. Average flight times for each group of athlete were approximately 0.04 s. Senior athletes showed more ‘typical’ race walking vertical force patterns than the juniors; this may be linked to quantity of training experience and gait efficiency. Athletes are advised to develop muscular strength endurance to cope with loading rates upon initial contact

Gait parameter differences between the legs during race walking

Prior research on the effects of fatigue during race walking has shown changes in step length and frequency (Knicker & Loch, 1990: New Studies in Athletics, 5, 25–38). It is unclear whether these changes are consistent for both legs. The purpose of the study was to investigate the differences between the legs for kinetic variables during race walking, and to measure changes occurring because of fatigue. The study was approved by the university’s ethics committee and informed consent was given by fourteen international race walkers, of whom four were females (age mean 28.2, s=7.4 years; stature 1.77, s=0.10 m; mass 66.0, s=11.7 kg). Each participant walked for 10 km on a treadmill (Gaitway, Traunstein). The average treadmill speed was 12.4 km h-1 (s=0.7) and each athlete walked at a constant pace. Data were recorded using the Gaitway treadmill, which has two in-dwelling force plates (Kistler, Winterthur). The sampling rate was 1000 Hz. Data were collected for 30 s at four times during the walk, at 2500 m, 4500 m, 6500 m and 8500 m. Statistical analysis consisted of repeated measures ANOVA. There was a significant difference between the legs for first peak force (F1,13=32.6, P¼0.001, Z2=0.71, power=0.99), weight acceptance rate (F1,13=14.5, P=.002, Z2=0.53, power=0.94), and push-off rate (F1,13=36.2, P=0.001, Z2=0.74, power=1), although these differences did not change significantly with distance walked. There was also a significant difference between the legs’ step lengths (F1,13=30.1, P=0.001, Z2=0.70, power=0.99), midsupport forces (F1,13=9.6, P=0.009, Z2=0.42, power=0.82), and propulsive force peaks (F1,13=20.6, P=0.001, Z2=0.61, power=0.99); the overall values for these variables also increased significantly with distance walked (P<0.001, P=0.009, and P<0.001 respectively). However, there was no effect of distance on the differences between the legs for any variable. The results show significant leg dominance during race walking. Athletes should be aware that these imbalances need rectification to prevent injury and maintain efficient walking technique. The imbalances did not appear to worsen with the onset of fatigue although this may occur over the longer championship distances of 20 and 50 km

Muscle activity of the stance knee in elite race walkers

The purpose of this study was to compare knee muscle activity in race walkers with different knee extension patterns. Three international athletes walked over two force plates recording at 1000 Hz. Video data were simultaneously recorded at 100 Hz; the digitised data were combined with the force data to calculate net muscle moments and joint powers. EMG testing was carried out on three muscles which cross the knee. The two walkers with legal techniques had similar moment and power patterns, whereas the non-legal walker experienced a longer period of eccentric flexor moment at the beginning of stance, which may have affected his ability to extend his knee correctly. After this, all three athletes experienced a period of isometric contraction at the knee. Achieving correct technique requires both strength endurance exercises and mobility development

Angular kinematics in elite race walking performance

The purpose of this study was to measure and analyse the important angular kinematic variables in elite race walking. Research has shown that these variables include knee angle at contact and midstance, rotation of the hips and shoulders, and hip extension velocity. Eighty elite race walkers were videoed during competition and analysed using 3D-DLT with SIMI Motion. The knee angle was found to be almost straight at contact in most athletes and hyperextended by the vertical upright position. Athletes varied in the amount of rotation at the hips and shoulders, with 50 km men having greater hip rotation and 20 km women having greater shoulder rotation. There was much more variation in the values found for elbow and shoulder angles. Very few angular measurements correlated with key race walking variables such as speed, step length and cadence

Differences between body segment parameter models in analysing elite race walkers in competition

The aim of this study was to measure differences in segment centre of mass position, velocity and acceleration in elite race walkers using two different body segment parameter models. Knowledge of how results differ between models can inform researchers as to the appropriate choice with regard to their own participants. Video data of thirty men and thirty women race walkers were recorded during competition using two camcorders operating at 50 Hz. Two popular body segment parameter models (Dempster and de Leva) were applied individually to the digitised data. Positional, velocity and acceleration values were obtained for each participant at four relevant points during the gait cycle. The whole body centre of mass vertical position was significantly lower when using the de Leva model compared to Dempster. The vertical position of the centre of the mass of the thigh was also significantly lower in women when using the de Leva model. The upper arm provided significantly different velocity and acceleration data at particular points between the models. The actual difference between positions of the centre of mass of the foot tended to be quite small. The analysis showed that the position of centres of mass (in the vertical direction) was most affected by choice of body segment parameter model. Differences in linear velocity and acceleration were largely non-significant, but extra care is advised when analysing the upper arm segment. Usage of de Leva’s model is recommended, particularly when analysing women participants

Technical characteristics of elite junior men and women race walkers.

AIM: Successful coaching in race walking requires a thorough understanding of the biomechanical principles underlying this unique form of gait. The purpose of this study was to analyze elite male and female junior race walkers and identify key kinematic variables. METHODS: Twenty junior men and 20 junior women were videoed as they competed over 10 km in the 8th European Cup Race Walking. Three-dimensional kinematic data were obtained using motion analysis software (SIMI, Munich). RESULTS: Step length and cadence were correlated with speed in both sexes, and greater step lengths were the kinematic reason for junior men's faster walking speeds. While cadence did not differ between junior men and junior women, there was a difference in proportion of step time spent in contact. There were some differences between genders for upper body joint angles (e.g., elbow) but there were few differences within lower limb joint angles. CONCLUSION: Although some technical aspects (e.g., pelvic and shoulder girdle rotation) appeared undeveloped, it was noteworthy that most athletes achieved full knee extension at initial contact in accordance with the rules. However, in many athletes flight times were evident that might present problems during the transition to the higher standards of senior competition. There was a large range of ability among both sexes and coaches are advised to ensure that technical development continues during the transition to senior competition

Gender and age-group differences in hip muscle activity patterns in elite race walkers

Race walking is a complex activity that relies on considerable power generation by the muscles at the hip joint. Little is known, however, whether differences are present in terms of muscle activity patterns between men and women, or between younger and older athletes. The purpose of this study was to compare hip muscle activity patterns in elite male and female race walkers across U20 and senior age groups. Ten male and ten female race walkers participated, with five U20 and five senior athletes of each gender. The athletes were recorded using high-speed videography (100 Hz) as they race walked down a 40 m runway, during which the muscle activity of the gluteus medius, gluteus maximus, biceps femoris and rectus femoris was recorded using electromyography (EMG) (1000 Hz). The hip sagittal angle was calculated from digitised data, and average rectified EMG used to identify visual differences between groups. No differences were found using ANOVA between any groups for the activity of any of the four muscles analysed at toe-off, midswing, heel-strike and midstance, although there were visual differences in activity timings. Overall the few differences between groups showed that race walking techniques are comparable across trained athletes and coaches can adopt similar training practices when developing the muscular qualities of their athletes

A WARM-UP INCLUDING A 5RM SQUAT PROTOCOL INCREASED BLOOD LACTATE, WITHOUT ALTERING THE SUBSEQUENT JUMP PERFORMANCE

The execution of an acute resistance exercise has shown to enhance a subsequent explosive movement; this enhancement is termed Post Activation Potentiation (PAP). PAP exists in conjunction with both acute metabolic and neuromuscular fatigue mechanisms which still are not fully understood. This study aimed to identify the effect of a five repetition maximum (5RM) back squat on vertical jump performance and blood lactate

THE MEASUREMENT OF KINETIC VARIABLES IN RACE WALKING

The purpose of this study was to measure kinetic variables during race walking. Forty national and international race walkers walked either 5 km or 10 km at a pace equivalent to 105% of their season’s best time. Junior athletes walked 5 km, while senior athletes (mostly 20 km walkers) walked 10 km. Kinetic data were collected using a Gaitway treadmill (1000 Hz). Data were collected at the 2.5 km point. Men had longer step lengths than women and walked faster as a result. There was little difference in cadence. Average flight times for each group of athlete were approximately 0.04 s. Senior athletes showed more ‘typical’ race walking vertical force patterns than the juniors; this may be linked to quantity of training experience and gait efficiency. Athletes are advised to develop muscular strength endurance to cope with loading rates upon initial contact

The contribution of the flight phase in elite race walking

Although race walkers are not permitted a visible flight phase, previous research has found that most competitors do experience very brief losses of contact. The purpose of this study was to assess the role of the flight phase in elite race walking. Seventeen international athletes race walked over two force plates recording at 1000 Hz. Video data were simultaneously recorded at 100 Hz and used to calculate kinematic variables such as step length. The mean flight time was 0.030 s (± .011) while the mean distance travelled during this phase was 0.12 m (± .05). It was calculated that without flight times, athletes would have slower mean velocities, particularly if mean cadence remained the same. However, the contribution of flight phases in race walking does not just allow for greater step lengths and faster speeds, but also more time for lower limb repositioning