Andrew Greenhalgh

The influence of barefoot and barefoot-inspired footwear on the kinetics and kinematics of running in comparison to conventional running shoes

Background: Barefoot running has been the subject of much attention in footwear biomechanics literature, based on the supposition that it serves to reduce the occurrence of overuse injuries in comparison to conventional shoe models. This consensus has led footwear manufacturers to develop shoes that aim to mimic the mechanics of barefoot locomotion. Objectives: This study compared the impact kinetics and three-dimensional (3-D) joint angular kinematics observed while running barefoot, in conventional cushioned running shoes and in shoes designed to integrate the perceived benefits of barefoot locomotion. The aim of the current investigation was therefore to determine whether differences in impact kinetics exist between the footwear conditions and whether shoes that aim to simulate barefoot movement patterns can closely mimic the 3-D kinematics of barefoot running. Method: Twelve participants ran at 4.0 m s−1 (±5%) in each footwear condition. Angular joint kinematics from the hip, knee and ankle in the sagittal, coronal and transverse planes were measured using an eight-camera motion analysis system. In addition, simultaneous tibial acceleration and ground reaction forces were obtained. Impact parameters and joint kinematics were subsequently compared using repeated-measures analyses of variance (ANOVAs). Results: The kinematic analysis indicated that, in comparison to the conventional and barefoot-inspired shoes, running barefoot was associated with significantly greater plantar–flexion at footstrike and range of motion to peak dorsiflexion. Furthermore, the kinetic analysis revealed that, compared to the conventional footwear, impact parameters were significantly greater in the barefoot condition. Conclusions: This study suggests that barefoot running is associated with impact kinetics linked to an increased risk of overuse injury when compared to conventional shod running. Furthermore, the mechanics of the shoes that aim to simulate barefoot movement patterns do not seem to closely mimic the kinematics of barefoot locomotion.

The Influence of Different Force and Pressure Measuring Transducers on Lower Extremity Kinematics Measured during Running

In running analyses where both kinetic and kinematic information is recorded, participants are required to make foot contact with a force and/or pressure measuring transducer. Problems arise if participants modify their gait patterns to ensure contact with the device. There is currently a paucity of research investigating the influence of different underfoot kinetic measuring devices on 3-dimensional kinematics of running. Fifteen participants ran at 4.0 m/s in four different conditions: over a floor embedded force plate, Footscan, Matscan, and with no device. Three-dimensional angular kinematic parameters were collected using an eight camera motion analysis system. Hip, knee, and ankle joint kinematics were contrasted using repeated-measures ANOVAs. Participants also rated their subjective comfort in striking each of the three force measuring devices. Significant differences from the uninhibited condition were observed using the Footscan and Matscan in all three planes of rotation, whereas participants subjectively rated the force plate significantly more comfortable than either the Footscan/Matscan devices. The findings of the current investigation therefore suggest that the disguised floor embedded force plate offers the most natural running condition. It is recommended that analyses using devices such as the Footscan/Matscan mats overlying the laboratory surface during running should be interpreted with caution.

Comparison of Pelvic Complex Kinematics During Treadmill and Overground Walking

OBJECTIVES To determine if there are changes in temporal gait parameters with a focus on pelvis when comparing overground and treadmill ambulation, and to assess the effect of sex. DESIGN An observational study employing motion analysis techniques to evaluate pelvic movement during gait. SETTING University biomechanics laboratory. PARTICIPANTS Men (n=8; 22.5±3.0 y) and women (n=6; 23.8±4.1 y). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Cadence, stride time, stance phase percent, and pelvic tilt, obliquity, and rotation parameters throughout the gait cycle were assessed during overground and treadmill walking. Kinematic data were recorded using a passive full body marker based motion analysis system. While an independent sample t test was used to determine if differences in walking speed were evident between sexes, a 2-way, repeated-measures analysis of variance was performed to examine the effect of walking mode and sex on each dependent variable. RESULTS Significant differences (P<.05) between overground and treadmill walking for the temporal parameters analyzed were evident for both sexes. A lower pelvic obliquity motion for treadmill walking when compared with overground walking was evident for both sexes, and the pelvic rotation movement pattern showed the greatest difference between walking modes. The majority of the significant differences between sexes were of a magnitude greater than the differences between overground and treadmill walking. CONCLUSIONS The differences in temporal and angular kinematics identified in the present study should be considered when treadmills are used in a rehabilitation program.

The effect of caffeine ingestion on skill maintenance and fatigue in epee fencers

Abstract The ergogenic effect of caffeine on sports performance focuses predominantly on endurance sports (Doherty & Smith, 2004) with little research on intermittent high intensity sports. This study aimed to explore the effect of caffeine ingestion on skill maintenance following fencing simulated exercise. Eleven competitive fencers participated (four female; seven male; age 33 ± 6.5 years). Following a maximal test to exhaustion, fencers completed two trials assessing accuracy and reaction times (Stroop test) before and after a fatiguing protocol designed to simulate the demands of a fencing competition. Skill testing involved 30 lunges to hit a target. 500 ml placebo or 3 mg · kg−1 caffeine supplemented drink was administered after the initial reaction and skill tests in a single-blind crossover design. The fatiguing protocol involved simulating six fights with 6-minute rests between each. Fencers rated their perceived exertion (arm, legs, overall) using the Borg scale. There was no overall effect of caffeine on total skill score (P = 0.40), however there was a tendency for fewer misses with caffeine (P = 0.10). Caffeine had no effect on the Stroop Test. Caffeine produced significantly lower perceived fatigue for overall (P < 0.01). These results provide some support for caffeine producing maintenance of skill and reducing perceived fatigue during fencing.

The Test-Retest Reliability of Anatomical Co-Ordinate Axes Definition for the Quantification of Lower Extremity Kinematics During Running

Three-dimensional (3-D) kinematic analyses are used widely in both sport and clinical examinations. However, this procedure depends on reliable palpation of anatomical landmarks and mal-positioning of markers between sessions may result in improperly defined segment co-ordinate system axes which will produce in-consistent joint rotations. This had led some to question the efficacy of this technique. The aim of the current investigation was to assess the reliability of the anatomical frame definition when quantifying 3-D kinematics of the lower extremities during running. Ten participants completed five successful running trials at 4.0 m·s-1 ± 5%. 3-D angular joint kinematics parameters from the hip, knee and ankle were collected using an eight camera motion analysis system. Two static calibration trials were captured. The first (test) was conducted prior to the running trials following which anatomical landmarks were removed. The second was obtained following completion of the running trials where anatomical landmarks were re-positioned (retest). Paired samples t-tests were used to compare 3-D kinematic parameters quantified using the two static trials, and intraclass correlations were employed to examine the similarities between the sagittal, coronal and transverse plane waveforms. The results indicate that no significant (p>0.05) differences were found between test and retest 3-D kinematic parameters and strong (R2≥0.87) correlations were observed between test and retest waveforms. Based on the results obtained from this investigation, it appears that the anatomical co-ordinate axes of the lower extremities can be defined reliably thus confirming the efficacy of studies using this technique.

Influence of footwear choice, velocity and surfaces on tibial accelerations experienced by field hockey participants during running

Field hockey is a physically demanding sport, exposing participants to potential overuse injuries linked to high levels of impact shock. This study evaluated the influence of footwear, surface and running velocity on impact shock in field hockey participants. Nine elite university male field hockey participants (age 21 ± 1.69 years, height 175.75 ± 6.56 cm and mass 78.13 ± 12.11 kg) volunteered for this study. A skin-mounted accelerometer was used to measure tibial impact shock during forward running at 3.3 and 5.0 m s−1 on concrete and a field hockey-specific synthetic sports surface (SSS), in a range of shoes (n = 5) typically worn by field hockey participants. A significant effect was found for surface and velocity. No significant differences were found between footwear conditions. The study concluded that reducing running velocity and participating in all field hockey activities on a suitable SSS may reduce the occurrence of injuries linked to impact shock in a field hockey population.

The impact of different footwear characteristics, of a ballet flat pump, on centre of pressure progression and perceived comfort

BACKGROUND Uncomfortable shoes have been attributed to poor fit and the cause of foot pathologies. Assessing and evaluating comfort and fit have proven challenging due to the subjective nature. The aim of this paper is to investigate the relationship between footwear characteristics and perceived comfort. METHODS Twenty-seven females assessed three different styles of ballet pump shoe for comfort using a comfort scale whilst walking along a 20 m walkway. The physical characteristics of the shoes and the progression of centre of pressure during walking were assessed. RESULTS There were significant physical differences between each style, square shoe being the shortest, widest and stiffest and round shoe having the least volume at the toe box. Centre of pressure progression angle was centralised to the longitudinal axis of the foot when wearing each of the three shoes compared to barefoot. Length, width and cantilever bending stiffness had no impact on perceived comfort. CONCLUSION Wearing snug fitting flexible soled round ballet flat pump is perceived to be the most comfortable of the shoe shapes tested producing a faster more efficient gait. Further investigations are required to assess impact/fit and upper material on perceived comfort to aid consumers with painful feet in purchasing shoes.

Investigation into the kinetics and kinematics during running in the heelless shoe

Background: Recent evidence suggests that runners who habitually rearfoot strike suffer higher rates of chronic injuries compared to those who adopt a mid/forefoot strike pattern. Based on this information new experimental heelless footwear was developed with the aim of mediating a mid/forefoot strike pattern.Objectives: The aim of the current investigation was to examine the three-dimensional (3D) kinematics and ground reaction forces (GRFs) of running in conventional footwear in comparison to the heelless shoes.Methods: Twelve male participants ran at 4.0 m.s−1±5% in each footwear condition. Angular joint kinematics from the hip, knee and ankle in the sagittal, coronal and transverse planes were measured using an eight-camera optoelectric motion capture system. Synchronous ground reaction forces were also obtained allowing impact load parameters and estimates of Achilles tendon force to be quantified. Differences in GRFs and 3D kinematics between footwear were assessed using paired t-tests.Results: The kinematic analysis indicated that, in comparison to the conventional running footwear, the heelless shoes were associated with significantly greater plantarflexion at foot strike and peak ankle eversion angle. Furthermore, the GRF analysis revealed that, compared to the conventional footwear, impact parameters were significantly lower in the heelless footwear.Conclusions: Given the reduction in impact loading rates and increases in ankle eversion that were observed in heelless footwear, running in this type of footwear may reduce the incidence of chronic injuries linked to excessive impact forces. However, it may increase the injury potential that is associated with excessive ankle eversion.

Varying degrees of running incline: Implications for chronic injury aetiology and rehabilitation

There has yet to be a combined analysis of the kinetics and three-dimensional kinematics of running at various degrees of inclination. The aim of the current study was to investigate the influence of treadmill running at various inclines (flat, 5, 10 and 15 degrees) on three-dimensional kinematics of the lower extremities and accelerations measured at the tibia. Ten male participants ran at 4.0 m/s at the four different inclinations. Three-dimensional lower extremity kinematics and tibial accelerations were quantified and contrasted using repeated measures ANOVAs. Tibial acceleration parameters were reduced significantly as a function of running incline, whilst tibial internal rotation was significant greater at 15° compared to flat. This study confirms that differences in both kinetics and kinematics are mediated through alterations in running inclination. From a clinical perspective, those who are susceptible/ recovering from injury may wish to utilise an incline in their training.

Comparison of pelvic complex kinematics during normal locomotion in treadmill vs. overground walking

Deviations from the normal movement pattern relates pathological gait. Conditions such as leg length inequality, increased lumbar lordosis and trunk bending relates to the abnormal kinematics of the pelvis. The assessment and rehabilitation of human locomotion is frequently assisted by a treadmill to simulate overground walking. Previous research suggest differences in temporal and angular kinematics when comparing treadmill to overground, questioning whether the treadmill replicates a similar setting as overground walking [1]. Similarly, treadmill running was commonly associated with increased anterior tilt when compared to overground. Furthermore, the investigations into the comparison of treadmill and overground running have produced conflicting results. Reported differences have been attributed to variations in surface, familiarisation, marker placement and identification protocol for toe off and heel strike [2, 3]. While, examining the effects of a lumbar corset on pelvic kinematics using a treadmill, a previous study indicated significant differences in rotations. However, no differences were reported in the sagittal and transverse planes [4]. Another investigation analysed the temporal differences of overground and treadmill walking and found at identical speeds, the stance period shortened by 6.7%, with increased cadence by 6.6% on the treadmill [5]. Similarly, Alton et al. [1] reported treadmill walking produced increases in cadence and decreases in stance time. Although, the treadmill has been described as advantageous in other comparative studies because of its convenience and the ease of control, the results reported in a previous study identified smaller ranges in the frontal and transverse anatomical plane for the pelvis whilst walking on the treadmill compared to overground. [4]. Furthermore, there are changes in variability and local stability for treadmill walking. In this context, another investigation concludes that treadmills may produce deceptive results [6]. When comparing overground and treadmill ambulation, the current study attempted to determine whether there are any reported or further differences in spatio temporal parameters of the pelvic complex and if these are related to gender differences.