Hard Shoes Research Articles

Spatiotemporal and Ground-Reaction Force Characteristics as Risk Factors for Running-Related Injury: A Secondary Analysis of a Randomized Trial Including 800+ Recreational Runners

Background: Running biomechanics may play a role in running-related injury development, but to date, only a few modifiable factors have been prospectively associated with injury risk. Purpose: To identify risk factors among spatiotemporal and ground-reaction force characteristics in recreational runners and to investigate whether shoe cushioning modifies the association between running biomechanics and injury risk. Study Design: Case-control study; Level of evidence, 3. Methods: Recreational runners (N = 848) were tested on an instrumented treadmill at their preferred running speed in randomly allocated, standardized running shoes (with either hard or soft cushioning). Typical kinetic and spatiotemporal metrics were derived from ground-reaction force recordings. Participants were subsequently followed up for 6 months regarding running activity and injury. Cox regression models for competing risk were used to investigate the association between biomechanical risk factors and injury risk, including stratified analyses by shoe version. Results: In the crude analysis, greater injury risk was found for greater step length (subhazard rate ratio [SHR], 1.01; 95% CI, 1.00-1.02; P = .038), longer flight time (SHR, 1.00; 95% CI, 1.00-1.01; P = .028), shorter contact time (SHR, 0.99; 95% CI, 0.99-1.00; P = .030), and lower duty factor (defined as the ratio between contact time and stride time; SHR, 0.95; 95% CI, 0.91-0.98; P = .005). In the stratified analyses by shoe version, adjusted for previous injury and running speed, lower duty factor was associated with greater injury risk in those using the soft shoes (SHR, 0.92; 95% CI, 0.85-0.99; P = .042) but not in those using the hard shoes (SHR, 0.97; 95% CI, 0.91-1.04; P = .348). Conclusion: Lower duty factor is an injury risk factor, especially for softer shoe use. Contrary to widespread beliefs, vertical impact peak, loading rate, and step rate were not injury risk factors in recreational runners. Registration: NCT03115437 (ClinicalTrials.gov identifier).

On-site personal protective equipment signage and use by road construction workers in Ghana: a comparative study of foreign- and locally-owned companies

BackgroundRoad construction work has specific risks and safety issues which have not been adequately addressed in most low- and middle-income countries, especially Africa. The objective of this study was to determine the prevalence of personal protective equipment (PPE) use during road construction activities by workers in foreign- owned against locally-owned road construction companies in Ghana.MethodsAn institution-based cross-sectional survey was undertaken during January – March, 2020 to study 389 road construction workers who were actively working on site. They were unobtrusively observed to capture whether or not they wore the appropriate PPE at the time of the survey. The PPE of interest were: hard hat, goggles, shoes, nose masks, hearing protection, gloves and reflective vests/apparel. On-site posted PPE signage was also checked.ResultsMajority of workers were males (96.9%) and labourers (53.5%). Similar numbers of workers in locally-owned (195) and foreign-owned (194) companies were studied. Use of PPE varied considerably by type: shoes (78.7%), reflective vest (44.5%), gloves (30.6%), hard hat (27.0%), nose mask (17.2%), goggles (11.3%) and hearing protection (10.8%). For all types of PPE, use was higher for workers in foreign-owned companies compared with locally-owned companies: goggles (Odds ratio [OR] 55.2), hearing protection (OR 52.0), gloves (OR 23.7), hard hat (OR 20.2), nose mask (OR 17.8), reflective vest (OR 5.3) and shoes (OR 4.1), (p<0.001 for all ORs). No site had any signage to promote PPE use.ConclusionsMajority of workers used shoes. Less than half of workers used other types of PPE and use of some types (goggles and hearing protection) was minimal. Workers in foreign-owned companies were significantly more likely to use all the seven types of PPE than locally-owned companies. Although there is still room for improvement in foreign-owned companies, locally-owned companies should be able to attain similar PPE use to that in foreign-owned companies. Necessary PPE should be provided and site supervisors should encourage workers to wear PPE when on site.

Characteristics of Eight Irish Dance LandingsConsiderations for Training and Overuse Injury Prevention.

Irish dance has evolved in aesthetics that lead to greater physical demands on dancers' bodies. Irish dancers must land from difficult moves without letting their knees bend or heels touch the ground, causing large forces to be absorbed by the body. The majority of injuries incurred by Irish dancers are due to overuse (79.6%). The purpose of this study was to determine loads on the body of female Irish dancers, including peak force, rise rate of force, and impulse, in eight common Irish hard shoe and soft shoe dance movements. It was hypothesized that these movements would produce different ground reac- tion force (GRF) characteristics. Sixteen female Irish dancers were recruited from the three highest competitive levels. Each performed a warm-up, reviewed the eight movements, and then performed each movement three times on a force plate, four in soft shoes and four in hard shoes. Ground reaction forces were measured using a three-dimensional force plate recording at 1,000 Hz. Peak force, rise rate, and vertical impulse were calculated. Peak forces normalized by each dancer's body weight for each of these variables were significantly different between move- ments and shoe types [F(15, 15)= 65.4, p < 0.01; F(15, 15) = 65.0, p < 0.01; and F(15, 15) = 67.4, p < 0.01, respectively]. The variable years of experience was not correlated with peak force, rise rate, or impulse (p > 0.40). It is concluded that there was a large range in GRF characteristics among the eight movements studied. Understanding the force of each dance step will allow instructors to develop training routines that help dancers adapt gradually to the high forces experienced in Irish dance training and competitions, thereby limiting the potential for overuse injuries.

Characteristics Of Eight Irish Dance Landings: Implications For Overuse Injury And Training

The aesthetics in Irish dance have evolved to create greater physical demands on dancer’s bodies. Irish dancers must land from difficult movements without letting their knees bend or heels touch the ground, causing large forces to be absorbed by the body. The majority of injuries incurred by Irish dancers are due to overuse (79.6%). PURPOSE: The purpose of this study was to determine loads on the body in female Irish dancers, including peak force, rise rate of force, and impulse in selected Irish hard shoe and soft shoe dance movements. It was hypothesized that the 8 movements would produce different GRF characteristics. METHODS: Sixteen female Irish dancers were recruited from the three highest competitive levels. Each performed a warm-up, reviewed 8 common Irish dance movements, and then performed each movement three times upon a force plate. Of the 8 movements, 4 were performed in soft shoes and 4 were performed in hard shoes. Ground reaction forces (GRFs) were measured using a three-dimensional force plate recording at 1000 Hz. Peak force, rise rate, and vertical impulse were calculated. GRFs were normalized by each dancer’s body weight. RESULTS: Peak forces, rise rates, and impulses were significantly different across movements (F = 65.4, p < 0.01; F = 65.0, p < 0.01; and F = 67.4, p < 0.01 respectively). The movement with the highest peak force was the stomp. The movement with the highest rise rate was the double-toe. The movement with the highest impulse was the leap. The skip had the lowest values for all GRFs measured. Individual peak forces ranged from 0.67-9.86 times body weight. Individual rise rates ranged from 10-147 body weights per second. Individual impulses ranged from −0.12 to 0.32 body weight seconds. Years of experience was not correlated with peak force, rise rate, or impulse (p > 0.40). CONCLUSIONS: There is a large range in GRF characteristics created by Irish dancers. Dance movements that have high average peak forces may be associated with higher risk of overuse injury. Irish dancers should use appropriate training methods to strengthen the tissues at greatest risk of overuse injury.

Shoe Cushioning Influences the Running Injury Risk According to Body Mass: A Randomized Controlled Trial Involving 848 Recreational Runners

Background: Shoe cushioning is expected to protect runners against repetitive loading of the musculoskeletal system and therefore running-related injuries. Also, it is a common belief that heavier runners should use footwear with increased shock absorption properties to prevent injuries. Purpose: The aim of this study was to determine if shoe cushioning influences the injury risk in recreational runners and whether the association depends on the runner’s body mass. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Healthy runners (n = 848) randomly received 1 of 2 shoe prototypes that only differed in their cushioning properties. Global stiffness was 61.3 ± 2.7 and 94.9 ± 5.9 N/mm in the soft and hard versions, respectively. Participants were classified as light or heavy according to their body mass using the median as a cut-off (78.2 and 62.8 kg in male and female runners, respectively). They were followed over 6 months regarding running activity and injury (any physical complaint reducing/interrupting running activity for at least 7 days). Data were analyzed through time-to-event models with the subhazard rate ratio (SHR) and their 95% confidence interval (CI) as measures of association. A stratified analysis was conducted to investigate the effect of shoe cushioning on the injury risk in lighter and heavier runners. Results: The runners who had received the hard shoes had a higher injury risk (SHR, 1.52 [95% CI, 1.07-2.16]), while body mass was not associated with the injury risk (SHR, 1.00 [95% CI, 0.99-1.01]). However, after stratification according to body mass, results showed that lighter runners had a higher injury risk in hard shoes (SHR, 1.80 [95% CI, 1.09-2.98]) while heavier runners did not (SHR, 1.23 [95% CI, 0.75-2.03]). Conclusion: The injury risk was higher in participants running in the hard shoes compared with those using the soft shoes. However, the relative protective effect of greater shoe cushioning was found only in lighter runners. Registration: NCT03115437 (ClinicalTrials.gov identifier)

Effect of shoe wearing time and midsole hardness on ground reaction forces, ankle stability and perceived comfort in basketball landing

ABSTRACT This study examined the effect of wearing time on comfort perception and landing biomechanics of basketball shoes with different midsole hardness. Fifteen basketball players performed drop landing and layup first step while wearing shoes of different wearing time (new, 2-, 4-, 6- and 8-week) and hardness (soft, medium and hard). Two-way ANOVA with repeated measures was performed on GRF, ankle kinematic and comfort perception variables. Increased wearing time was associated with poorer force attenuation and comfort perception during landing activities (p < 0.05). The new shoes had significantly smaller forefoot (2- and 4-week) and rearfoot peak GRF impacts (all time conditions) in drop landing and smaller rearfoot peak GRF impact (6- and 8-week) in layup; shoes with 4-week of wearing time had significantly better perceptions of forefoot cushioning, forefoot stability, rearfoot cushioning, rearfoot stability and overall comfort than the new shoes (p < 0.05). Compared with hard shoes, the soft shoes had better rearfoot cushioning but poorer forefoot cushioning (p < 0.05). Shoe hardness and wearing time would play an influential role in GRF and comfort perception, but not in ankle kinematics. Although shoe cushioning performance would decrease even after a short wearing period, the best comfort perception was found at 4-week wearing time.

Physiological Demands of Hard Shoe and Soft Shoe Irish Dancing: A Pilot Study

MP. Trebour, MM. Cutten, TG. Coffey, LQ. Jimenez, JP. Morrison. Longwood University, Farmville, VA 23909 PURPOSE: Irish Step Dance is a form of dance characterized by maintaining an upright posture and primarily moving the lower extremities with two different shoe styles. Soft shoe (SS) dance requires light and delicate movements, while hard shoe (HS) dance requires forceful and powerful movements. Irish dance competition pieces can last 30-60 seconds and performance pieces can last 10 minutes. The purpose of this study was to characterize the cardiorespiratory demands of female recreational Irish dancers. METHODS: Seven female dancers (35.8±9.6 y; 166.6±7.5 cm; 79.1±13.1 kg) volunteered for HR monitoring during three separate 45 min classes (n=16 measurements). Classes consisted of a mixture of HS and SS dancing. Three female dancers (28.0±13.9 y; 168.7±1.2 cm; 76.5±15.2 kg) volunteered for VO2 testing. Dancers completed a three minute reel and treble reel dances while wearing soft and hard shoes. Steady-state data were analyzed from the last 30 sec of the three minute dance test. The order of testing was randomized and the same piece of music was used for all dances. RESULTS: The mean HR for a class session was 128±14 bpm (69.7±9.3 %HRmax). The mean maximal HR achieved in class was 184±10 bpm (93.9±8.7 %HRmax). There was no significant (p<0.05) difference in VO2 (HS 23.33±7.51 ml/kg/min; SS 23.57±6.17 ml/kg/min), R-value (HS 1.31±0.05; SS 1.31±0.12), HR (HS 184.7±8.7 bpm; SS 185.0±2.0 bpm), or %HRmax (HS 96.3±3.2 %HRmax; SS 94.5±3.7 %HRmax) for HS and SS dance. CONCLUSIONS: The class data suggest that Irish dance classes are a moderate intensity activity with vigorous intensity intervals. Hard shoe and soft shoe Irish dance are physiologically demanding aerobic activities with anaerobic contribution. Despite differences in dance style these data suggest that there is no difference between the metabolic demands of HS and SS Irish dancing.

Optimized reference spectrum for rating the impact sound insulation of concrete floors.

It has been long recognized that the single-number quantities presented in the standard ISO 717-2 [(2013) International Organization for Standardization] do not correlate especially well with the subjective judgment of living impact sound sources directed to the floors. The aim of this study was to find single-number quantities which are well associated with the subjective annoyance caused by different impact sounds. Experimental data of laboratory measurements of impact sound insulation of floors and a psychoacoustic experiment was used [Kylliäinen et al. (2017). Acta Acust. Acust. 103, 236-251]. The five studied impact sound types were walking with hard shoes, socks, and soft shoes, super ball bouncing, and chair moving. A fundamental requirement was that the single-number quantities can be expressed as the sum of L'n,w or L'n T, w and a spectrum adaptation term. Reference spectra were derived by the means of a mathematical optimization method. Reference spectra for each sound type were defined separately. An optimized reference spectrum based on all five sound types explained the annoyance of these sound types reasonably well (r2 = 0.93) and better than any of the standardized single number quantities (e.g., r2 = 0.86 for L'n,w + CI,50-2500).

Modeling the central nervous system functionality in controlling the calf muscle activity during running with sport shoes.

Biological findings show that the activity of the calf muscle group is controlled by the central nervous system during running. The central nervous system tries to retain the peak values of the ground reaction force at constant levels as well as to minimize the vibration amplitude of soft tissues of the lower leg. Furthermore, these objectives are functions of stiffness and damping (compliance properties) of the calf muscle-tendon unit, especially gastrocnemius-Achilles. In this article, a new model for the calf muscle-tendon unit activity is presented in which the coefficients of stiffness and damping are exponential functions of the force produced at the Achilles tendon in the duration of stance phase, that is, they are time variant instead of having constant values. Then, the central nervous system functionality to control the activity of the muscle-tendon unit is formulated through definition of an optimization problem. This problem is solved by additionally considering the hardness of sport shoes. The muscle activity is indeed controlled via optimally adjusting two tuning parameters of the muscle-tendon unit model in terms of the hardness of shoes. This idea is examined separately for two running speeds. The results show the following: (1) The hardness of shoes affects the muscle activity. We find safe areas of the hardness parameters to design sport shoes. (2) When hard shoes are worn, the running speed has negligible effects on the tuning parameters, while with soft shoes the tuning parameters significantly change the muscle activity and the ground reaction force depended on running speed. (3) The ability of muscle in changing its compliance properties (specified by bound limits over the muscle-tendon unit tuning parameters) has the most influence in the safe area. (4) Rising running speed leads to a decrease in the safe area of shoes' parameters.

Effects of Different Hardness in Bionic Soles on Lower Limb Biomechanics

The design of modern footwear seems to have an excessive protective effect on the function of the foot. The purpose of this study was to examine how bionic shoes designed would influence the biomechanical index of gait patterns. There were 10 male subjects underwent gait analysis. Normal sports shoes (NS) with flat-soles were selected as control shoes. The experimental shoes comprising of two elasticity levels were defined as soft-sole bionic shoes (SS) and hard-sole bionic shoes (HS). We examined ground reaction forces, plantar pressures and angles of the ankle, knee and hip during walking and jogging conditions. In comparison with standard shoes, wearing bionic shoes reduced the range of motion in some joints during movement and changed the peak angle in the sagittal, frontal and horizontal planes. Moreover, the vertical average loading rates were significantly larger than that of the standard shoes during jogging. The experimental groups showed larger PP or PTI in the foot regions examined except in the lateral forefoot. Also, increases the in the contact area of the midfoot with decreases in the contact area in heel were also observed. In some regions of the foot, the hard sole of the bionic shoes had a lower pressure than that of the soft sole. These findings indicate that the design of the bionic sole in this study can be used to increase toe scratching ability, increase neuromuscular strength and enhance stability and proprioceptive ability. However, the higher plantar pressures in some regions may increase the risk of overuse injuries. The findings from the study indicate preference for the hard bionic shoes during exercise compared to the soft sole.

Shoe cushioning affects lower extremity joint contact forces during running

This study evaluated the effect of running shoes with differing midsole cushioning on ankle, knee and hip contact forces during running. Joint contact forces were estimated in 40 recreational runners (28 female, 12 male) while running over ground in three shoe conditions. Shoes differed only in midsole cushioning (45, 57 and 70 Asker C). Three-dimensional kinetics and kinematics were collected during running and input to a musculoskeletal model to estimate internal axial forces at the ankle, knee and hip. Multivariate ANOVA suggested that more cushioned shoes, relative to less cushioned shoes, reduced peak joint contact forces (p < 0.01) and load rates (p < 0.01). Ankle joint contact force and load rate were reduced with increased cushioning (p < 0.01) with moderate to large effects observed between pairwise comparisons (p ≤ 0.01–0.05, dz=0.41–1.35). Cushioning effects were also observed for knee joint contact force (p = 0.03) and loading rate (p < 0.01) with load reduction only seen when comparing the soft and hard shoes (p ≤ 0.05, dz=0.41–0.44). Midsole cushioning had less of an effect on hip contact force (p = 0.31) although hip contact force loading rate was influenced by midsole cushioning (p < 0.01) with lower rates observed for soft versus medium and hard shoe comparisons (p ≤ 0.01, dz=0.41–0.62). These results suggest that increasing shoe cushioning properties ∼10–20% may benefit individuals susceptible to high loads at the ankle, and to a lesser extent knee and hip, during running.

Influence of shoe midsole hardness on plantar pressure distribution in four basketball-related movements

ABSTRACTThis study examined how shoe midsole hardness influenced plantar pressure in basketball-related movements. Twenty male university basketball players wore customized shoes with hard and soft midsoles (60 and 50 Shore C) to perform four movements: running, maximal forward sprinting, maximal 45° cutting and lay-up. Plantar loading was recorded using an in-shoe pressure measuring system, with peak pressure (PP) and pressure time integral (PTI) extracted from 10 plantar regions. Compared with hard shoes, subjects exhibited lower PP in one or more plantar regions when wearing the soft shoes across all tested movements (Ps < 0.05). Lower PTI was also observed in the hallux for 45° cutting, and the toes and forefoot regions during the first step of lay-up in the soft shoe condition (Ps < 0.05). In conclusion, using a softer midsole in the forefoot region may be a plausible remedy to reduce the high plantar loading experienced by basketball players.

Effects of Muscle Fatigue on the Ground Reaction Force and Soft-Tissue Vibrations During Running: A Model Study

A modeling approach is used in this paper to study the effects of fatigue on the ground reaction force (GRF) and the vibrations of the lower extremity soft tissues. A recently developed multiple degrees-of-freedom mass-spring-damper model of the human body during running is used for this purpose. The model is capable of taking the muscle activity into account by using a nonlinear controller that tunes the mechanical properties of the soft-tissue package based on two physiological hypotheses, namely, "constant force" and "constant vibration." In this study, muscle fatigue is implemented in the model as the gradual reduction of the ability of the controller to tune the mechanical properties of the lower body soft-tissue package. Simulations are carried out for various types of footwear in both pre- and postfatigue conditions. The simulation results show that the vibration amplitude of the lower body soft-tissue package may considerably increase (up to 20%) with muscle fatigue, while the effects of fatigue on the GRF are negligible. The results of this modeling study are in line with the experimental studies that found muscle fatigue does not significantly change the GRF peaks, but may increase the level of soft-tissue vibrations (particularly for hard shoes). A major contribution of the current study is the formulation of a hypothesis about how the central nervous system tunes the muscle properties after fatigue.

Impairment in people with anterior cruciate ligament reconstruction in adjusting ground reaction force in running

ABSTRACTIn healthy individuals, maximum vertical ground reaction force (MVGRF) remains close to constant during constant velocity running, despite variation in stiffness of the surface underfoot. Because the anterior cruciate ligament (ACL) possesses mechanoreceptors that influence recruitment of knee muscles, it may play a role in regulation of lower limb force output. This study was designed to examine the effect of recent ACL reconstruction on MVGRF in running. Seven patients who were 5–13 weeks post-ACL reconstruction and 7 healthy participants ran for 60 seconds in shoes modified with hard and with soft 1-cm outsoles. The MVGRF during running was measured for the ACL reconstructed and nonsurgical limbs of patients and limbs of healthy participants. The difference in MVGRF between running in hard and soft shoes was significantly greater in ACL reconstructed limbs than nonsurgical limbs (p = 0.003) and compared to limbs of healthy participants (p = 0.001). In contrast, a difference in MVGRF between shoes was not found between patients' nonsurgical limbs and those of healthy participants. A lack of mechanoreceptive feedback from the ACL graft may be among the factors explaining the difference between the ACL reconstructed limbs and the other two limb conditions.

Flotation Device, and: A Version of Her Suicide: in the North of Ireland

Flotation Device, and: A Version of Her Suicide: in the North of Ireland Deirdre O’Connor (bio) Flotation Device I dreamt my waist got small overnight. My breasts changed too, seemed perky and new hovering above the slimmer middle of me, a cinched skirt. I was Cocktail Barbie watching TV during hurricane season: aftermath and forecast, in between. Things could not be told apart. The screen showed a model island being drowned, muck and pumps. The orange swath of the storm was the shape my skirt took bogging down, until I changed again, darkened like the black girls on TV, the doll I’d been to someone cast away, a failed raft, clutched in my own dead hand. [End Page 194] A Version of Her Suicide: In the North of Ireland She dreamt her loneliness a loosening flock of starlings over the walled city, and she, a girl again in hard shoes echoing as she passed up Waterloo, through Butcher’s Gate, and into the city’s heart. Soldiers gone, graffiti fading, peace more or less achieved. And yet the absence of human strife that she was never a part of ricocheted amid the architecture, its need to escape upwards. Maybe she wanted to shake the cobbled order of ground, so silence could be heard clearly again. More than heard. [End Page 195] Deirdre O’Connor Deirdre O’Connor directs the Writing Center at Bucknell University, where she also serves as associate director of the Bucknell Seminar for Younger Poets. Her first book, Before the Blue Hour, received the Cleveland State Poetry Prize and was published in 2002. She is seeking a publisher for a second book manuscript, tentatively titled Notes on Disappearance. Her work has appeared in Poetry, Natural Bridge, Hayden’s Ferry Review, Painted Bride Quarterly, Poetry Daily, and other journals and anthologies. Copyright © 2009 Frontiers Editorial Collective, Inc

Distal Chevron Osteotomy for Moderate to Severe Hallux Valgus Deformity in Patients Aged 50 or Older

Purpose: The purpose of this study was to analyze the clinical and radiological results of distal chevron osteotomy in patients aged 50 and older with moderate-to-severe hallux valgus. Materials and Methods: The authors reviewed the medical records and radiographs of 19 patients (26 feet). Average age at time of surgery was 58 years and the mean follow-up period was 3 years and 1 month. For radiological evaluation, we analyzed changes in hallux valgus angles and 1 st -2 nd intermetatarsal angles after index operations. Clinical results were assessed with respect to pain, activities of daily living, and shoe-wear. Results: Hallux valgus angles and 1 st -2 nd intermetatarsal angles improved, but considerable correction loss occurred with time. This correction loss was found to be significantly correlated with preoperative subluxation of the 1st metatarsophalangeal joint and the 1 st -2 nd intermetatarsal angle. Clinically, remarkable improvements were achieved in terms of pain and level of activity, but most patients (except 4) still wore comfortable shoes rather than hard shoes at latest follow-ups. Conclusion: Distal chevron osteotomy is beneficial for patients aged 50 and older with moderate-tosevere hallux valgus deformity, but correction loss may occur in patients with marked subluxation of the 1 st metatarsophalangeal joint or a severe 1 st -2 nd intermetatarsal angle.

The role of engineering in fatigue reduction during human locomotion — a review

The purpose of this review is to discuss how an athlete’s fatigue can be limited by using recent innovations in sports engineering. The review focuses on human locomotion, i.e. mainly fatigue during endurance sports. First, through a general definition and illustrations of means of locomotion such as running, cycling, walking/hiking or speed skating, several aspects of fatigue reduction will be presented. With regards to the mechanical stress, it has been shown that (i) contrary to ‘invitro’ experiments and, in comparison with hard shoes, soft shoes do not appear to reduce impact forces during running and (ii) too much cushioning can have side effects in terms of energy cost and thus in terms of fatigue in running and mountain biking. On the contrary, the equipment weight-that also depends on the weight repartition may have dramatic effects in terms of fatigue. Any equipment allowing better mechanical efficiency (e.g. chainrings, klapskate) or work distribution (e.g. walking with poles) can potentially reduce an athlete’s fatigue under similar conditions without this equipment. However, among elite athletes, the use of technical innovation does not seem to affect fatigueper se but provides performance improvement with similar fatigue occurrence. It appears that fatigue-related improvements caused by technical innovations only occur among sportsmen exercising for leisure. In the second part of this review, recent textile innovations aimed at decreasing fatigue by the use of elastic compression stockings or at regulating temperature will be discussed. Finally, two methods designed to improve recovery after training or competition (elastic compression and electromyostimulation) will be discussed. Both these techniques are widely used by elite athletes despite relatively poor scientific evidence of their efficiency, with the exception of recovery after eccentric exercise.

The Influence of Midsole Cushioning on Mechanical and Hematological Responses during a Prolonged Downhill Run

The purpose of this study was to investigate the influence of midsole durometer on mechanical and hematological responses during a prolonged downhill run. Twenty-four men completed a 30-min downhill run (-12% grade) wearing either soft, medium, or hard midsole shoes. Data describing mean peak tibial acceleration (PTA), stride frequency, plasma free hemoglobin, hemoglobin concentration, hematocrit, and creatine kinase (CK) were collected. While there were no significant differences in PTA among midsole durometer shoes, PTA increased by 20% after the first 5 min of the run over all other time intervals during the run (p < .05). Hemolysis showed a 50.2% increase from prerun to postrun values (p < .05). CK increased from the prerun state to 24 hr after the run (p < .05). Downhill running, irrespective of midsole durometer, showed increased levels of leg shock, hemolysis, and muscle damage over values that are present in the literature for a level running protocol.

The Effect of Varying Midsole Hardness on impact Forces and Foot Motion during Foot Contact in Running

The purpose of this study was to investigate the influence of midsole hardness on both impact forces and rearfoot motion. Seven trained male long-distance runners were assessed with a Kistler force plate and with high-speed video, while running at 4.5 ± 0.1 m · s"1 with soft and hard shoe soles (EVA; soft shore Asker C40; hard shore Asker C65). The results showed smaller initial vertical impact peaks, occurring with a higher loading rate, and a significantly larger and faster initial eversion when subjects ran with hard shoes. Support is given to the concept that a more pronounced initial eversion offers an additional deceleration mechanism (Stacoff, Denoth, Kaelin, &amp; Stuessi, 1988) also increasing the eccentric loading of the inverting muscles. On the other hand, during midstance soft shoe soles were found to produce a larger maximum eversion and pronation, also imposing an increased load on the same muscles. So, a good running shoe should be focused on a balance between reducing impact forces and reducing overpronation.

The Introduction of an Eye Protection Programme

The implementation of an eye protection programme into a factory is probably one of the biggest challenges a Management faces in its Safety Programme. This is because, firstly, no-one likes wearing eye protection. With prescription spectacles there is an immediate benefit—with them we can see clearly; without them, vision for certain functions is either blurred or symptoms of discomfort may result. However, with piano safety spectacles, there is not an immediate benefit. The benefit only applies when an eye injury Is prevented. Secondly, supervisors and shop stewards will face a multitude of questions, complaints and reasons why eye protection should not be worn. These questions will need to be dealt with quickly and 1competently and, as we proceed, the need for professional assistance will be obvious. The eye protection programme should be an integral part of the general Safety programme. However, as it is more sophisticated than most other segments of the general programme, e.g., the hard hat, safety shoes or gloves programmes, it is better to leave it until later in the programme when the whole company is more safely orientated in their thinking. Frequently In commencing a safety programme one may be tempted to rush in and provide the whole work force with eye protection; this way, everyone can see that ‘something’ is being done towards safety. However, experience has proven it is much better to wait until the general programme is well established. There are two methods of equipping employees with eye protection. The first is to purchase a quantity of multifit pianos, place them in the general store and then hope employees will requisition them from the store and wear them. Naturally, this idea seldom works. Employees don't wear spectacles and if complaints arise, little reliable information is available to deal with them. The second method Is to implement a comprehensive eye protection programme.