quinta-feira, 5 de janeiro de 2012

Does Altitude Training Improve Sea Level Performance In Endurance Athletes?


Physical training at altitude is thought to invoke similar physiological changes to those caused by endurance training at sea level. The adaptations considered most important for performance enhancement include increases in blood haemoglobin and myoglobin, improved buffering capacity and improved aerobic enzymes in the muscles.

It is postulated that the stress of hypoxic exposure, in addition to training stress will compound the training adaptations the athlete experiences and therefore be an advantage over sea level training (Wolski et al 1996). 


Residing at altitude allows a number of potentially beneficial physiological, ventilatory, haematological and metabolic adaptations to occur. These adaptations are postulated to improve endurance exercise performance. While is widely supported that training at altitude enhances performance at altitude, there is much less support for the view that altitude training will improve sea level endurance performance.
It is now theorized that the reason that many studies found no improvement in sea level performance after altitude training is due to the fact relative deconditioning appears to occur while training at altitude, which may offset the potential beneficial changes resulting from altitude exposure.
Therefore a new strategy has been introduced where the athletes live at altitude but train at sea level. This approach allows both the beneficial adaptations of acclimatization to develop, as well as provide the opportunity to train without reducing power output during exercise. Therefore, this strategy is accumulating support from scientists, athletes, and coaches alike, as the most advantageous method for enhancing sea level performance in highly trained endurance athletes.
In conclusion, well trained athletes whose development has included adequate base preparation with regular, high intensity interval work, and have reached a plateau in their training response at sea level are likely to derive the most benefit from altitude training using the LHTL approach.


quarta-feira, 4 de janeiro de 2012

Chocolate tem o mesmo efeito que fazer exercício

E se o chocolate fizer tão bem como o exercício?
Os benefícios da ingestão de pequenas quantidades de chocolate preto já são bem conhecidas, mas um grupo de cientistas descobriu agora que o seu efeito nos músculos pode ser o mesmo do exercício físico.
Os investigadores norte-americanos envolvidos neste estudo concluíram que uma das substâncias encontradas no chocolate, a epicatequina, parece desencadear a mesma resposta muscular que o exercício vigoroso. Na base desta teoria estão as mitocôndrias, responsáveis pela produção de energia das células.
“As mitocôndrias produzem energia que é usada pelas células do corpo. Mais mitocôndrias implicam a produção de mais energia”, explica um dos cientistas, Moh Malek, da Universidade de Wayne State, em Detroit.
“Exercício aeróbico, como correr ou andar de bicicleta, aumenta o número de mitocôndrias nas células dos músculos. O nosso estudo descobriu que a epicatequina desencadeia a mesma resposta, sobretudo dos músculos cardíacos e esqueléticos”, sublinha o investigador.
Durante 15 dias, um tipo específico de epicatequina do cacau foi dado a ratos duas vezes por dia. Os roedores também faziam 30 minutos diários de treino.
Os investigadores concluíram que os animais que apenas recebiam epicatequina tinham a mesma capacidade física do que os que corriam.

terça-feira, 3 de janeiro de 2012

Get Low

It's about hip angle......

    Shorter cranks can help you get comfortable in a more extreme aero position.
    Hip angle—the angle between the rider’s torso and legs—might be the most important factor in determining a rider’s ability to comfortably produce power on a bike. Chances are you’ve experienced the significance of hip angle yourself. If you lower your shoulders either by crouching down or by dropping your bars, you will eventually reach a point at which pedaling becomes less comfortable and maintaining power is a struggle. Tri bike geometry is designed to help maintain a comfortable hip angle when riding in a crouched aerodynamic position, but even on a tri bike, all riders have a limit to how tightly they can crunch themselves at the hips. Raising the aerobars is the most common way to open hip angle, but this can compromise aerodynamics, handling and even limit the bikes you can ride. Crank length—not just frame geometry and aerobar position—impacts hip angle, yet most athletes riding triathlon-specific bikes are still using conventional road bike crank lengths. Mat Steinmetz, a Retül bike fitter in Boulder, Colo., measured the influence of crank length and aerobar drop on hip angle using Retül’s 3-D measurement system to see how crank length affects hip angle.
    Although hip angle is typically measured between the ankle, hips and shoulders with the rider’s leg fully extended and the crank at the 6 o’clock position, hip angle at the most compact 12 o’clock position is the fit dimension that prevents most riders from lowering their bars.
    Wider hip angle = more comfortable position
    Steinmetz found that shortening the crank arms by 1cm opens hip angle by 2–3 degrees. Raising the aerobars by 2cm had approximately the same effect.
    Use it yourself: If you are trying to lower your aerobars but can’t drop any farther, swap your cranks for a set with arms 1cm shorter and you might be able to drop your bars another 2cm below your saddle!
    By Mat Steinmetz with Aaron Hersh
    Aaron Hersh

    Aaron Hersh

    Aaron Hersh is the Senior Tech Editor of Triathletemagazine. Aaron writes a column every Thursday for Triathlete.com called "Ask Aaron". To submit a question, write Aaron at Askaaron@competitorgroup.com.