Despite an intuitive relationship between technique and both running economy (RE) and performance, and the diverse techniques used by runners to achieve forward locomotion, the objective importance of overall technique and the key components therein remain to be elucidated.PurposeThis study aimed to determine the relationship between individual and combined kinematic measures of technique with both RE and performance.MethodsNinety-seven endurance runners (47 females) of diverse competitive standards performed a discontinuous protocol of incremental treadmill running (4-min stages, 1-km·h−1 increments). Measurements included three-dimensional full-body kinematics, respiratory gases to determine energy cost, and velocity of lactate turn point. Five categories of kinematic measures (vertical oscillation, braking, posture, stride parameters, and lower limb angles) and locomotory energy cost (LEc) were averaged across 10–12 km·h−1 (the highest common velocity < velocity of lactate turn point). Performance was measured as season's best (SB) time converted to a sex-specific z-score.ResultsNumerous kinematic variables were correlated with RE and performance (LEc, 19 variables; SB time, 11 variables). Regression analysis found three variables (pelvis vertical oscillation during ground contact normalized to height, minimum knee joint angle during ground contact, and minimum horizontal pelvis velocity) explained 39% of LEc variability. In addition, four variables (minimum horizontal pelvis velocity, shank touchdown angle, duty factor, and trunk forward lean) combined to explain 31% of the variability in performance (SB time).ConclusionsThis study provides novel and robust evidence that technique explains a substantial proportion of the variance in RE and performance. We recommend that runners and coaches are attentive to specific aspects of stride parameters and lower limb angles in part to optimize pelvis movement, and ultimately enhance performance.
OBJECTIVEPatients with diabetes with peripheral neuropathy have a well-recognized increased risk of falls that may result in hospitalization. Therefore this study aimed to assess balance during the dynamic daily activities of walking on level ground and stair negotiation, where falls are most likely to occur. RESEARCH DESIGN AND METHODSGait analysis during level walking and stair negotiation was performed in 22 patients with diabetic neuropathy (DPN), 39 patients with diabetes without neuropathy (D), and 28 nondiabetic control subjects (C) using a motion analysis system and embedded force plates in a staircase and level walkway. Balance was assessed by measuring the separation between the body center of mass and center of pressure during level walking, stair ascent, and stair descent. RESULTSDPN patients demonstrated greater (P < 0.05) maximum and range of separations of their center of mass from their center of pressure in the medial-lateral plane during stair descent, stair ascent, and level walking compared with the C group, as well as increased (P < 0.05) mean separation during level walking and stair ascent. The same group also demonstrated greater (P < 0.05) maximum anterior separations (toward the staircase) during stair ascent. No differences were observed in D patients. CONCLUSIONSGreater separations of the center of mass from the center of pressure present a greater challenge to balance. Therefore, the higher medial-lateral separations found in patients with DPN will require greater muscular demands to control upright posture. This may contribute to explaining why patients with DPN are more likely to fall, with the higher separations placing them at a higher risk of experiencing a sideways fall than nondiabetic control subjects.Patients with diabetic peripheral neuropathy (DPN) have an altered gait strategy (1-3) and a fivefold increased risk of falling (4-6). Falling is a major health risk in many developed countries; for example, in the general U.K. population, over a quarter of accidents that required hospital treatment were the result of a fall (7). A fall is preceded by loss of balance, which may be recoverable in some individuals, but requires rapid responses and a high level of strength from the lower-limb muscles (8,9). Nevertheless, the more likely an individual is to lose balance, the more likely they will at some point experience a fall. Therefore, quantifying balance control
OBJECTIVEAlthough patients with diabetic peripheral neuropathy (DPN) are more likely to fall than age-matched controls, the underlying causative factors are not yet fully understood. This study examines the effects of diabetes and neuropathy on strength generation and muscle activation patterns during walking up and down stairs, with implications for fall risk. RESEARCH DESIGN AND METHODSSixty-three participants (21 patients with DPN, 21 diabetic controls, and 21 healthy controls) were examined while walking up and down a custom-built staircase. The speed of strength generation at the ankle and knee and muscle activation patterns of the ankle and knee extensor muscles were analyzed. RESULTSPatients with neuropathy displayed significantly slower ankle and knee strength generation than healthy controls during stair ascent and descent (P < 0.05). During ascent, the ankle and knee extensor muscles were activated significantly later by patients with neuropathy and took longer to reach peak activation (P < 0.05). During descent, neuropathic patients activated the ankle extensors significantly earlier, and the ankle and knee extensors took significantly longer to reach peak activation (P < 0.05). CONCLUSIONSPatients with DPN are slower at generating strength at the ankle and knee than control participants during walking up and down stairs. These changes, which are likely caused by altered activations of the extensor muscles, increase the likelihood of instability and may be important contributory factors for the increased risk of falling. Resistance exercise training may be a potential clinical intervention for improving these aspects and thereby potentially reducing fall risk.Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes, affecting up to 50% of older patients (1,2). It is characterized by sensory loss in the lower limbs, altered sense of joint position, and impaired muscular function, which can result in alterations to gait (1-5). Patients with neuropathy are five times more likely to fall than age-matched controls, with over half of patients reporting at least one fall per year (6,7). Falls while walking down stairs account for 60% of all fall-related deaths, making this activity 10 times more hazardous than level-ground walking (8).
The influence of running speed and sex on running economy is unclear and may have been confounded by measurements of oxygen cost that do not account for known differences in substrate metabolism, across a limited range of speeds, and differences in performance standard. Therefore, this study assessed the energy cost of running over a wide range of speeds in high-level and recreational runners to investigate the effect of speed (in absolute and relative terms) and sex (men vs women of equivalent performance standard) on running economy. To determine the energy cost (kcal · kg−1 · km−1) of submaximal running, speed at lactate turn point (sLTP), and maximal rate of oxygen uptake, 92 healthy runners (high-level men, n = 14; high-level women, n = 10; recreational men, n = 35; recreational women, n = 33) completed a discontinuous incremental treadmill test. There were no sex-specific differences in the energy cost of running for the recreational or high-level runners when compared at absolute or relative running speeds (P > .05). The absolute and relative speed–energy cost relationships for the high-level runners demonstrated a curvilinear U shape with a nadir reflecting the most economical speed at 13 km/h or 70% sLTP. The high-level runners were more economical than the recreational runners at all absolute and relative running speeds (P < .05). These findings demonstrate that there is an optimal speed for economical running, there is no sex-specific difference, and high-level endurance runners exhibit better running economy than recreational endurance runners.
including titles -250 words, Total -2'948 words Funding Statement Funded by a Clinical Research Grant from the European Foundation for the Study of Diabetes (EFSD) Conflicts of InterestThe authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest in the subject matter or materials discussed in this manuscript. Novelty StatementHere we examined for the first time, the effects of a resistance exercise based intervention on speed of knee and ankle strength generation in people with diabetic peripheral neuropathy, during stair ascent and descent. We observed that after a 16 week intervention, people with diabetic peripheral neuropathy, and people with diabetes without neuropathy, increased the speed at which strength was developed at the ankle and knee during stair ascent and descent. This is expected to decrease the risk of falling during these movements. Therefore, such exercises could be incorporated into a multi-faceted exercise programme to improve safety in people with diabetes and diabetic peripheral neuropathy.Aims: People with diabetic peripheral neuropathy (DPN) are slower at generating strength at the ankle and knee, leading to unsteadiness during stair negotiation tasks.This study examines the effects of a 16-week resistance exercise training intervention on the speed of ankle and knee strength generation during stair ascent and descent, in people with neuropathy.Methods: Forty three participants: 9 patients with DPN; 13 patients with diabetes but no neuropathy (D) and 21 healthy controls (H-CON) ascended and descended a custombuilt staircase. The speed at which ankle and knee strength were generated, and muscle activation patterns of the ankle and knee extensor muscles were analyzed before and after a 16-week intervention period.Results: Ankle and knee strength generation during both stair ascent and descent were significantly higher post-intervention compared to pre-intervention in the participants with diabetes who undertook the resistance exercise intervention (p<0.05). Although muscle activations were altered by the intervention, there were no observable patterns that underpinned the observed changes. Conclusions:The increased speed of ankle and knee strength generation observed after the intervention, are expected to improve stability during the crucial weight acceptance phase of stair ascent and descent, and ultimately contribute towards reducing the risk of falling. Improvements in muscle strength as a result of the resistance exercise training intervention are expected to be the most influential factor for increasing the speed of strength generation It is advocated that these exercises could be incorporated into a multi-faceted exercise programme to improve safety in people with diabetes and neuropathy.
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