Justin Lange

Comprehensive evaluation of player-surface interaction on artificial soccer turf.

The purpose of this study was to evaluate the traction characteristics of four different stud configurations on Fédération Internationale de Football Association (FIFA) 2-Star, third-generation artificial soccer turf. The investigated stud configurations were hard ground design, firm ground design, soft ground design, and an experimental prototype. The concept of this study combines performance, perception, biomechanical, and mechanical testing procedures. Twenty-five soccer players took part in the different testing procedures. Variables of this study were: running times, subjective rankings/ratings, ground reaction forces, and mechanical traction properties. Statistical discrimination between the four stud configurations was shown for performance, perception, and biomechanical testing (p < 0.05). Unsuited stud configurations for playing on artificial turf are characterized by less plain distributed and pronounced studs.

Printed MWCNT-PDMS-Composite Pressure Sensor System for Plantar Pressure Monitoring in Ulcer Prevention

In this paper, a low cost and flexible plantar pressure monitoring system is presented that is suited for everyday use to prevent pressure ulcers. To define the technical specifications of the sensor system, a gait analysis study was carried out. Analysis of measured data based on a multivariate approach and neural network classification shows that it is possible to dissociate between healthy and unhealthy rollover patterns. To implement a pressure sensor element, a multiwalled carbon nanotube (MWCNT)-polydimethylsiloxane (PDMS)-composite was selected. A sensor matrix made of the composite was fully printed to enable pressure distribution measurements. As a final application, a printed insole was fabricated with six single MWCNT-PDMS pressure sensors that were situated on characteristic points of the insole to detect the unhealthy rollover patterns. Its functionality to measure plantar pressures was proven on a human foot inside a running shoe during walking.

Pelvic Belt Effects on Health Outcomes and Functional Parameters of Patients with Sacroiliac Joint Pain.

Introduction The sacroiliac joint (SIJ) is a common source of low back pain. However, clinical and functional signs and symptoms correlating with SIJ pain are widely unknown. Pelvic belts are routinely applied to treat SIJ pain but without sound evidence of their pain-relieving effects. This case-control study compares clinical and functional data of SIJ patients and healthy control subjects and evaluates belt effects on SIJ pain. Methods 17 SIJ patients and 17 healthy controls were included in this prospective study. The short-form 36 survey and the numerical rating scale were used to characterize health-related quality of life in patients in a six-week follow-up and the pain-reducing effects of pelvic belts. Electromyography data were obtained from the gluteus maximus, biceps femoris, rectus femoris and medial vastus. Alterations of muscle activity, variability and gait patterns were compared in patients and controls along with the belts’ effects in a dynamic setting when walking. Results Significant improvements were observed in the short-form 36 survey of the SIJ patients, especially in the physical health subscores. Minor declines were also observed in the numerical rating scale on pain. Belt-related changes of muscle activity and variability were similar in patients and controls with one exception: the rectus femoris activity decreased significantly in patients with belt application when walking. Further belt effects include improved cadence and gait velocity in patients and controls. Conclusions Pelvic belts improve health-related quality of life and are potentially attributed to decreased SIJ-related pain. Belt effects include decreased rectus femoris activity in patients and improved postural steadiness during locomotion. Pelvic belts may therefore be considered as a cost-effective and low-risk treatment of SIJ pain. Trial Registration ClinicalTrials.gov NCT02027038

Carbon nanotube composite for application in gait analysis

Ulceration as a complication of diabetes mellitus is caused by high recurrent pressures at the foot, which may even lead to amputation. Risk factors of diabetic foot ulcers are diabetes, polyneuropathy and obesity. A gait analysis study including healthy, obese and diabetic persons was accomplished to determine characteristic plantar pressure distribution patterns between these groups. By analyzing the resulting roll-over-patterns, it should be possible to derive better sensor design criteria for new pressure sensing systems tailored on the specific disease pattern. The current available instruments for measurement of plantar pressure distribution are prone to mechanical overload and too expensive for everyday treatment of patients with diabetic foot syndrome. Thus a new low-cost, flexible pressure sensor system is in development. Therefore a pressure sensitive carbon nanotube-polymer composite was prepared and stencil printed on polymer foil. The printing process enables also the economical production of a flexible, piezoresistive film. The resistance change under applied load on the nanotube-polymer film was investigated using compression tests.

Relationship between plantar pressure and perceived comfort in military boots

Although comfort is an important feature in military boots, especially during long marches, there is a lack of information about the relationship between plantar pressure and perceived comfort of military boots in marching conditions. The influence of plantar pressure on perception of comfort has been shown for athletic and casual footwear (Chen et al. 1994, Jordan et al. 1997). The authors showed that peak pressures are coherent with perceived comfort in most plantar foot regions. They pointed out that insole characteristics are an important factor for the distribution and magnitudes of plantar pressure as well for the perceived shoe comfort. Therefore, it is necessary to understand the way boot comfort is perceived and how it can be increased to develop military boots. Furthermore, the risk of sustaining a stress fracture is increased in military recruit populations (Milgrom et al. 1985), but relationship between the bending stiffness of military boots, increased peak pressures and resulting metatarsal strain has only been partially assessed up to date (Arndt et al. 2003). Hence the aim of the study was to determine the relationship of perceived comfort and plantar pressures in military boots during realistic marching conditions. Furthermore, boots were also tested mechanically in order to clarify any relationship between boot’s bending stiffness and plantar pressure as well as between boot’s bending stiffness and perceived comfort.

Reduced plantar sensation leads to heterogeneous reactions in plantar pressure distribution during normal walking

Many studies have determined the influence of provoking reduced plantar foot sensitivity on plantar pressure distribution patterns during the roll-over process (ROP) [1-3], but differ considerably in their approaches and results. This raises the question of whether the method of provoking decreased plantar foot sensitivity is responsible for the different results or whether subjects respond so differently that there is no uniform ROP reaction. Therefore, the aim of this study was to evaluate individual response patterns in the ROP after provoking reduced plantar foot sensitivity and to consider the homogeneity of this reaction pattern within the sample.