Footwear designed to enhance energy return improves running economy compared to a minimalist footwear: does it matter for running performance?

The present study compared the effects of a footwear designed to enhance energy return (thermoplastic polyurethane, TPU) vs minimalist shoes on running economy (RE) and endurance performance. In this counterbalanced and crossover design study, 11 recreational male runners performed two submaximal constant-speed running tests and two 3-km time-trials with the two shoe models. Oxygen uptake was measured during submaximal constant-speed running tests in order to determine the RE at 12 km/h and oxygen cost of running (CTO2) at individual average speed sustained during the 3-km running time-trials wearing either of the two shoes. Our results revealed that RE was improved (2.4%) with TPU shoes compared with minimalist shoes (P=0.01). However, there was no significant difference for CTO2 (P=0.61) and running performance (P=0.52) comparing the TPU (710±60 s) and the minimalist (718±63 s) shoe models. These novel findings demonstrate that shoes with enhanced mechanical energy return (i.e. TPU) produced a lower energy cost of running at low (i.e., 12 km/h) but not at high speeds (i.e., average speed sustained during the 3-km running time-trial, ∼15 km/h), ultimately resulting in similar running performance compared to the minimalist shoe.

Running economy in elite soccer and futsal players: differences among positions on the field / Economia de corrida em jogadores de futebol e futsal de elite: diferenças entre as posições em campo

OBJECTIVE: To determine running economy in a large sample of elite soccer and futsal players to obtain benchmarks in different positions. METHODS: Running Economy is the energy demand at a submaximal running velocity. Players were divided into 6 subgroups. Soccer: defenders, midfielders, and strikers; futsal: defenders, wingers, and pivots. Elite soccer players (n=129) and elite futsal players n=72 performed an incremental running test starting at 8.4 km.h-1 with increments of 1.2 km.h-1 every two minutes on a treadmill until exhaustion. Running Economy was determined by interpolation between ventilatory thresholds 1 and 2 (VT1 and VT2). RESULTS: Running Economy (measured as mL.kg-1.km-1) was compared between the playing positions in the two team sports. In soccer, running economy was 222.7 (defenders), 227.0 (midfielders), and 219.8 (strikers) mL.kg-1.km-1, respectively. In futsal, the corresponding values were 198.5 (defenders), 196.9 (wingers), and 190.5 (pivots) mL.kg-1.km-1, respectively. We no found significantly differences between the three positions in both sports. The Running Economy of futsal players was 12.5% better than that of soccer players. Running Economy correlated positively with oxygen uptake at VT2 in both sports and in all positions. CONCLUSION: Futsal players exhibited better Running Economy than soccer players; this should be considered as a factor in the athlete's training plan.

OBJETIVO: Determinar a Economia de Corrida numa grande amostra de jogadores de futebol e futsal de elite em diferentes posições do campo. METODOS: Os jogadores foram subdivididos em três subgrupos: futebol (jogadores de defesa, meio-campistas e atacantes) e futsal (jogadores de defesa, alas e pivôs). Foram 129 jogadores de futebol e 72 jogadores de futsal, que competem nas respectivas primeiras divisões do Brasil. Os jogadores foram submetidos a teste de esforço em esteira (8,4 km-1.h+1,2km-1.h a cada dois minutos) até a exaustão. Consumo máximo de oxigênio, limiares ventilatórios e Economia de Corrida foram registrados por análise de troca gasosa respiratória. A Economia de Corrida foi determinada por interpolação utilizando as velocidades dos limiares ventilatórios 1 e 2 e o consume de oxigênio nas duas velocidades. RESULTADOS: Os valores de Economia de Corrida entre as posições nos dois esportes foram os seguintes: Futebol, jogadores de defesa (222,7±16,7mL.kg-1.km-1), meio-campistas (227±19,9mL.kg-1.km-1), e atacantes (219,8±17,2mL.kg-1.km-1). Futsal, jogadores de defesa (198,5±10,8mL.kg-1.km-1), alas (196,9±16,2mL.kg-1.km-1), e pivôs (190,5±11,8mL.kg-1.km-1). Não foram encontradas diferenças significativas entre as três posições em ambos os esportes. A Economia de Corrida dos jogadores de futsal foi 12,5% melhor do que dos jogadores de futebol. Neste estudo, os jogadores da posição pivô no futsal tiveram os melhores valores de Economia de Corrida (custo de oxigênio mais baixo). Embora o consumo máximo de oxigênio (VO2max) e o limiar ventilatório 2 (LV2) fosse maior nos jogadores de futebol, a Economia de Consumo foi pior. Esta correlacionou-se positivamente com o VO2 no LV2 em ambos os esportes e em todas as posições CONCLUSÃO: Futsal tem melhor Economia de Consumo do que futebol. O presente estudo aponta a importância dos índices Economia de Consumo no plano de treinamento físico dos atletas.

The effect of bio-resonance on healthy young persons' walking efficiency——A pilot study / 中华物理医学与康复杂志

Objective To explore the effect of bio-resonance on walking efficiency in healthy youths. Methods Ten young male participants were involved in this study (age 16 ± 2 years, height 1.73 ±:0. 1 m and weight 56. 1 ± 7 kg). The time-space data were collected using a motion analysis system, and oxygen cost was meas-ured with a Cosmed K4b2 portable gas analysis system. Walking at a self-selected, comfortable walking frequency was recorded through three dimensional gait analysis. Each participant walked at 100% , 80% and 120% of their comfortable walking frequency. Results The average 100% , 80% and 120% comfortable walking frequencies were 107.60 ± 1.78, 85.80 ± 7.45 and 128.60 ±10.46 steps/min, respectively. Oxygen consumption at the three frequencies was significantly different (P≤0.01), and the oxygen costs were 0. 140 ± 0.011, 0. 193 ± 0. 049 and 0. 192 ± 0. 035 ml/m/kg, respectively. Above or below the self-selected pace, oxygen cost increased significantly (P ≤0.05). Conclusion There is an inherited bio-resonance in human walking, and walking with this natural rhythm is reflected in the lowest oxygen cost. Any change from the natural walking rhythm may result in increased en-ergy expenditure and decreased efficiency.

Comparison of Energy Consumption According to The Joint Deformities of The Lower Extremity in Sagittal Plane / 대한정형외과학회잡지

Background. Ultimate goal for the treatment of the deformities in the lower extremities is to minimize the energy requirement and conserve the energy on walking and daily living. The normal energy saving mechanism is usually broken down in the patients with the deformities in the lower extremity, and they need more energy consumption. This is the reason why they feel fatigue frequently. It is well known that the deformity in the lower extremity cause excessive energy consumption. Objectives. There is no report that compared the energy consumption according to the deformities of the lower extremity. When we decide the priority of the treatment in cases of multiple deformities, it will be important to understand the energy demand according to each deformity. Therefore, it is the purpose of this study that assess the energy consumption according to the various types of lower extremity deformities. Method. We induced the multiple deformities in ten normal adults with the brace artificially. The induced deformities are as follows: Equinus deformity; mild (10degrees), moderate (20degrees), severe (30degrees), Knee flexion deformity; mild (10degrees), moderate (20degrees), severe (30degrees), Hip flexion deformity; mild (10degrees), moderate (20degrees), severe (30degrees). For the control group, same braces were applied without any deformity. Oxygen consumption was measured for the energy consumption with the Oxygen Consumption Meter (Morgan Oxylog II, Morgan Ltd. England). Heart rate was checked with the Telemonitor (Dynascope, Fukuda Ltd, Japan). We evaluated the inspired volume, oxygen rate, oxygen cost, and heart rate in each group and compared the data among the groups. Result. Energy consumption was higher in the hip deformity group, in the knee deformity group, and in the ankle deformity group in that order. Conclusion. When there are concomitant deformities in hip, knee and ankle, the priority of treatment may be hip, knee and ankle, in that order in terms of energy consumption.