Exercise performance of many sport disciplines (eg, team sports, racquet sports, short and mid-distance running) requires both high endurance and muscle power output capabilities. 1 , 2 Usually, these specific physical capabilities are developed separately, but the increasing number of
Guillaume P. Ducrocq, Thomas J. Hureau, Olivier Meste and Grégory M. Blain
Alex Stacoff, Xaver Kaelin, Edgar Stuessi and Bernhard Segesser
In the research of running shoes, excessive pronation is often related to various running injuries. Anatomically, pronation is a movement that occurs in more than one joint. Previous investigations that evaluated the pronation in running studied the movements of the lower leg and the rearfoot only. However, pronation could also be influenced by the movement of the forefoot and therefore depend on the torsional stiffness of the foot and of the shoe sole. This study investigated the relationship between the torsion and the pronation in running with a rearfoot touchdown and with a forefoot touchdown. The results show that, compared to running barefoot, running with a shoe decreases torsion and thereby increases pronation significantly (p < 0.01) for the forefoot and rearfoot touchdown conditions. Thus the reduction of torsional movement due to stiff shoe soles could well be a reason for running injuries caused by excessive pronation. It is concluded that modern running shoes could be designed to allow a certain torsional movement of the foot.
Jeffery J. Summers, Victoria J. Machin and Gregory I. Sargent
This study was designed to examine some of the psychosocial factors underlying the recent marathon boom. A survey of 459 marathoners varying in age, sex, ability, and experience was conducted to assess their reasons for running a marathon, the outcomes derived, and their experiences during a marathon. Information was also sought regarding the psychological aspects of running in general, particularly the concept of addiction to running. Measures of addiction to running produced a consistent pattern of sex differences, with females evidencing higher levels of addiction than males. With respect to reasons for running a marathon and perceived outcomes, some interesting trends were evident as a function of age. It was suggested that the attraction of the marathon to people of all ages and abilities may lie partly in its unique ability to satisfy a wide range of needs, both extrinsic and intrinsic.
Hugh Trenchard, Andrew Renfree and Derek M. Peters
Drafting in cycling influences collective behavior of pelotons. Although evidence for collective behavior in competitive running events exists, it is not clear if this results from energetic savings conferred by drafting. This study modeled the effects of drafting on behavior in elite 10,000-m runners.
Using performance data from a men’s elite 10,000-m track running event, computer simulations were constructed using Netlogo 5.1 to test the effects of 3 different drafting quantities on collective behavior: no drafting, drafting to 3 m behind with up to ~8% energy savings (a realistic running draft), and drafting up to 3 m behind with up to 38% energy savings (a realistic cycling draft). Three measures of collective behavior were analyzed in each condition: mean speed, mean group stretch (distance between first- and last-placed runner), and runner-convergence ratio (RCR), which represents the degree of drafting benefit obtained by the follower in a pair of coupled runners.
Mean speeds were 6.32 ± 0.28, 5.57 ± 0.18, and 5.51 ± 0.13 m/s in the cycling-draft, runner-draft, and no-draft conditions, respectively (all P < .001). RCR was lower in the cycling-draft condition but did not differ between the other 2. Mean stretch did not differ between conditions.
Collective behaviors observed in running events cannot be fully explained through energetic savings conferred by realistic drafting benefits. They may therefore result from other, possibly psychological, processes. The benefits or otherwise of engaging in such behavior are as yet unclear.
Dietmar Wallner, Helmut Simi, Gerhard Tschakert and Peter Hofmann
To analyze the acute physiological response to aerobic short-interval training (AESIT) at various high-intensity running speeds. A minor anaerobic glycolytic energy supply was aimed to mimic the characteristics of slow continuous runs.
Eight trained male runners (maximal oxygen uptake [VO2max] 55.5 ± 3.3 mL · kg−1 · min−1) performed an incremental treadmill exercise test (increments: 0.75 km · h−1 · min−1). Two lactate turn points (LTP1, LTP2) were determined. Subsequently, 3 randomly assigned AESIT sessions with high-intensity running-speed intervals were performed at speeds close to the speed (v) at VO2max (vVO2max) to create mean intensities of 50%, 55%, and 60% of vLTP1. AESIT sessions lasted 30 min and consisted of 10-s work phases, alternated by 20-s passive recovery phases.
To produce mean velocities of 50%, 55%, and 60% of vLTP1, running speeds were calculated as 18.6 ± 0.7 km/h (93.4% vVO2max), 20.2 ± 0.6 km/h (101.9% vVO2max), and 22.3 ± 0.7 km/h (111.0% vVO2max), which gave a mean blood lactate concentration (La) of 1.09 ± 0.31 mmol/L, 1.57 ± 0.52 mmol/L, and 2.09 ± 0.99 mmol/L, respectively. La at 50% of vLTP1 was not significantly different from La at vLTP1 (P = .8894). Mean VO2 was found at 54.0%, 58.5%, and 64.0% of VO2max, while at the end of the sessions VO2 rose to 71.1%, 80.4%, and 85.6% of VO2max, respectively.
The results showed that AESIT with 10-s work phases alternating with 20 s of passive rest and a running speed close to vVO2max gave a systemic aerobic metabolic profile similar to slow continuous runs.
Marc Sim, Brian Dawson, Grant Landers, Dorine W. Swinkels, Harold Tjalsma, Debbie Trinder and Peter Peeling
The effect of exercise modality and intensity on Interleukin-6 (IL-6), iron status, and hepcidin levels was investigated. Ten trained male triathletes performed 4 exercise trials including low-intensity continuous running (L-R), low-intensity continuous cycling (L-C), high-intensity interval running (H-R), and high-intensity interval cycling (H-C). Both L-R and L-C consisted of 40 min continuous exercise performed at 65% of peak running velocity (vVO2peak) and cycling power output (pVO2peak), while H-R and H-C consisted of 8 × 3-min intervals performed at 85% vVO2peak and pVO2peak. Venous blood samples were drawn pre-, post-, and 3 hr postexercise. Significant increases in postexercise IL-6 were seen within each trial (p < .05) and were significantly greater in H-R than L-R (p < .05). Hepcidin levels were significantly elevated at 3 hr postexercise within each trial (p < .05). Serum iron levels were significantly elevated (p < .05) immediately postexercise in all trials except L-C. These results suggest that, regardless of exercise mode or intensity, postexercise increases in IL-6 may be expected, likely influencing a subsequent elevation in hepcidin. Regardless, the lack of change in postexercise serum iron levels in L-C may indicate that reduced hemolysis occurs during weight-supported, low-intensity activity.
Michael S. Cherry, Sridhar Kota, Aaron Young and Daniel P. Ferris
Although there have been many lower limb robotic exoskeletons that have been tested for human walking, few devices have been tested for assisting running. It is possible that a pseudo-passive elastic exoskeleton could benefit human running without the addition of electrical motors due to the spring-like behavior of the human leg. We developed an elastic lower limb exoskeleton that added stiffness in parallel with the entire lower limb. Six healthy, young subjects ran on a treadmill at 2.3 m/s with and without the exoskeleton. Although the exoskeleton was designed to provide ~50% of normal leg stiffness during running, it only provided 24% of leg stiffness during testing. The difference in added leg stiffness was primarily due to soft tissue compression and harness compliance decreasing exoskeleton displacement during stance. As a result, the exoskeleton only supported about 7% of the peak vertical ground reaction force. There was a significant increase in metabolic cost when running with the exoskeleton compared with running without the exoskeleton (ANOVA, P < .01). We conclude that 2 major roadblocks to designing successful lower limb robotic exoskeletons for human running are human-machine interface compliance and the extra lower limb inertia from the exoskeleton.
James W. Navalta, Jeffrey Montes, Nathaniel G. Bodell, Charli D. Aguilar, Ana Lujan, Gabriela Guzman, Brandi K. Kam, Jacob W. Manning and Mark DeBeliso
population is utilizing wearable technology. Among the most common leisure activities is hiking, which has seen participation increase almost 200 fold in recent years, and is one of the top two outdoor activities performed ( Cordell et al., 2005 ; Manning et al., 2015 ). Additionally, trail running has seen
Gareth N. Sandford, Sian V. Allen, Andrew E. Kilding, Angus Ross and Paul B. Laursen
Preparation for 800-m running represents a unique challenge to the middle-distance coach. With close interplay required between aerobic and anaerobic/neuromuscular physiology, athletes with distinctly different profiles have an opportunity for success in the event. Recently, a “changing of the
Nicola Giovanelli, Filippo Vaccari, Mirco Floreani, Enrico Rejc, Jasmine Copetti, Marco Garra, Lea Biasutti and Stefano Lazzer
to the best of our knowledge the effects of SMFR on running performance have not been investigated yet. The energy cost of running (Cr) plays a relevant role in determining performance among middle- and long-distance runners along with the maximal oxygen uptake and the fraction of it that is