Elias K. Tomaras

Less is more: standard warm-up causes fatigue and less warm-up permits greater cycling power output

The traditional warm-up (WU) used by athletes to prepare for a sprint track cycling event involves a general WU followed by a series of brief sprints lasting ≥ 50 min in total. A WU of this duration and intensity could cause significant fatigue and impair subsequent performance. The purpose of this research was to compare a traditional WU with an experimental WU and examine the consequences of traditional and experimental WU on the 30-s Wingate test and electrically elicited twitch contractions. The traditional WU began with 20 min of cycling with a gradual intensity increase from 60% to 95% of maximal heart rate; then four sprints were performed at 8-min intervals. The experimental WU was shorter with less high-intensity exercise: intensity increased from 60% to 70% of maximal heart rate over 15 min; then just one sprint was performed. The Wingate test was conducted with a 1-min lead-in at 80% of optimal cadence followed by a Wingate test at optimal cadence. Peak active twitch torque was significantly lower after the traditional than experimental WU (86.5 ± 3.3% vs. 94.6 ± 2.4%, P < 0.05) when expressed as percentage of pre-WU amplitude. Wingate test performance was significantly better (P < 0.01) after experimental WU (peak power output = 1,390 ± 80 W, work = 29.1 ± 1.2 kJ) than traditional WU (peak power output = 1,303 ± 89 W, work = 27.7 ± 1.2 kJ). The traditional track cyclists WU results in significant fatigue, which corresponds with impaired peak power output. A shorter and lower-intensity WU permits a better performance.

Should postactivation potentiation be the goal of your warm-up?

Athletes expect improved high-intensity performance following warm-up, and postactivation potentiation (PAP) is assumed to contribute to this improvement. However, the scientific evidence supporting this assumption is incomplete. PAP is known to result from prior muscle activation, and should enhance maximal effort contractions of very short duration. However, PAP dissipates over 4-6 min after the PAP-inducing contraction, so PAP should not contribute to enhanced performance more than 5 min after the warm-up.

Softer and more resilient running shoe cushioning properties enhance running economy

Purpose: Several studies have investigated whether shoe cushioning properties have an effect on running economy. However, the findings have not been unanimous. Studies have shown both increases and decreases in running economy with soft shoes, while other studies have shown participant specific differences. Therefore, the purpose of this study was to add to the body of knowledge describing the effects of shoe cushioning properties on running economy. Methods: This study was comprised of two experiments; one using a stationary metabolic analysis system to measure oxygen consumption during treadmill running, and one using a portable metabolic analysis system to measure oxygen consumption during over-ground running. Twelve aerobically fit athletes participated in each experiment. Two professionally constructed pairs of prototype running shoes were provided by adidas AG for this experiment (Soft shoe and Control shoe). The shoes were identical in construction with the only differences being the midsole material and corresponding stiffness and energy return. Results: For both the treadmill and over-ground experiments, the Soft shoe condition was associated with statistically significantly decreased oxygen consumption compared to the Control shoe condition (Treadmill p = 0.044, Over-ground p = 0.028). In the treadmill experiment, 10 of the 12 subjects consumed less oxygen while wearing the more compliant/resilient condition, with an average decrease for all subjects of 1.0%. In the over-ground experiment 9 of the 12 subjects consumed less oxygen while running in the more compliant/resilient condition, with an average decrease for all subjects of 1.2%. Conclusion: Running shoes with softer and more resilient midsoles were found to influence running economy by 1.0% on average during treadmill and over-ground experiments.

Running shoe cushioning properties can influence oxygen consumption

adidas have recently launched a new running shoe midsole material. Termed ‘Boost’, these midsoles are comprised of expanded thermoplastic polyurethane (TPU) pellets. Compared to ethylene vinyl acetate (EVA), Boost material is claimed to be more compliant and have less energy loss. It has been hypothesised and theoretical studies have shown that energy return in footwear can have an influence on running performance (Nigg and Segesser 1992, Shorten 1993, Stefanyshyn and Nigg 2000). Therefore, the reduced energy loss of TPU midsoles may provide runners with a functional benefit. However, this remains to be verified experimentally.

Soccer shoe bending stiffness significantly alters game-specific physiology in a 25-minute continuous field-based protocol

The purpose of this study was to investigate the effects of soccer shoes with differing bending stiffness on physiological and performance variables in a game-like situation. A sample of 13 male soccer players was recruited to complete this study. Three soccer shoes with different forefoot bending stiffness (low, medium, high) were compared using a continuous field-based work protocol (the Soccer-25). Participants performed the Soccer-25 while the physiological (rate of oxygen consumption, heart rate, ventilation, and rate of energy expenditure) and performance variables (drill completion times) were recorded. The Soccer-25 consists of seven phases, Drills 1–3 and Shuttle Runs 1–4. A one-way repeated measures ANOVA was used to determine whether there were any significant effects for soccer shoe condition for each of the physiological and performance variables. The medium-stiffness shoe was significantly lower than the high-stiffness shoe for a number of physiological variables, including global oxygen consumption (p = 0.044), heart rate during Drills 2 (p = 0.043), ventilation during Shuttle Run 4 (p = 0.016), global energy expenditure (p = 0.043), and rate of energy expenditure during Drills 1 (p = 0.044). The low stiffness shoe was not significantly different from the medium- or high-stiffness shoes. No significant differences were found for any of the performance variables. Soccer shoe forefoot bending stiffness significantly affects the physiological variables in a game-like situation.

Forefoot bending stiffness, running economy and kinematics during overground running

Previous research has shown that altering forefoot (FF) bending stiffness can enhance running economy; however, the mechanism behind the changes in running economy remains unknown. Therefore, the purpose of this study was to investigate the relationship between forefoot bending stiffness, running economy, and lower limb kinematics during overground running. Eighteen aerobically fit recreational male athletes performed overground running using a portable metabolic analysis system to measure oxygen consumption in two footwear conditions with different forefoot bending stiffness. Sagittal plane kinematic data of the metatarsophalangeal, ankle, and knee joints were recorded using a high-speed camera. On average, there was no difference in running economy when running in the Stiff shoe (O2 = 38.1 ± 5.4 mL/kg/min) compared to the Control shoe (O2 = 37.7 ± 5.8 mL/kg/min, p = 0.11). On an individual basis, 10 athletes (Responders) improved their running economy with increased FF bending stiffness (∆O2 = −2.9%), while eight athletes (Non-Responders) worsened or did not improve their running economy in a stiff shoe (∆O2 = +1.0%). In stiff footwear, Responders experienced kinematic changes at the ankle joint (decreased angular velocity) that likely resulted in decreased energy requirement for muscular contractions due to a presumed shift on their individual force–velocity relationship. The lack of improvement in running economy by the Non-Responders may be attributed to a presumed lack of a shift in the force–velocity relationship of the calf musculature. Instead, Non-Responders experienced kinematic changes (increased ankle plantarflexion during push phase with stiff footwear) that likely hindered their moment-generating capability potentially due to a shift on their individual force–length relationship. These findings represent important progress towards explaining inter-individual changes in running economy with different footwear bending stiffness.