Cut the cardio for weight loss
Excessive cardio can cause muscle fibre conversion which is not beneficial for a strength trainer or a bodybuilder. As the body adapts aerobically, muscles start to oxidise fat in order to produce as much aerobic energy as possible. There is a conversion of fast twitch IIb fibres to IIa and eventually type I (slow twitch). This is bad because fast twitch fibres have the greatest potential for growth and strength. Increased muscle mass is also related to an increase in metabolic rate, so eventually a lower body fat %.
Cardiovascular training also has a detrimental effect on the central nervous system. Repeated low intensity aerobic activity confuses the brain, so when it comes time to recruit a maximum number of muscle fibres for a lift, it may not be able to, due to aerobic adaptations. It has also been shown that cardiovascular training decreases insulin sensitivity, meaning the body does not effectively drive nutrients into the muscle cells due to a lack of insulin receptors. All that cardio you are doing may in fact be making you fatter, not leaner.
What are the alternatives?! Well there are plenty. HIIT (High intensity interval training) is great, as the body performs maximal efforts for short periods of time.
This emphasises fast twitch fibre recruitment and a longer period of raised metabolism. Circuit resistance work such as complexes, are another great alternative as they keep the body in an anabolic state while sending your heart rate through the roof! The main thing which should be manipulated in order to attain a lean physique is to diet. Eat quality food, hit the weights hard and you’ll be lean in no time.