I get this question often:
I have an history of doing lots of aerobic type sports like rowing, road cycling and cross-country skiing 10-14 hours a week. I just took up weight training three months ago, but my gains are slow to come. My exercise physiologist friend says that it is the reason why my gains have been slow in coming. Is he right? Am I screwed for life?
Your friend is right…for a short while… the good news is that you are not screwed for life. Your gains in strength are slow to come for three physiological reasons: conversion of fiber type, central nervous system adaptations and hormonal adaptations. Let me expand on these aerobic physiological adaptations
It has been shown that people who have done high volumes of aerobic work have fast-twitch fibers that behave like slow-twitch fibers. In other words, their fast-twitch fibers have greater endurance, smaller diameters, have slower time to peak force and are weaker. The fast-twitch fibers normally have large diameters, have short type to peak force, and are stronger, but because in this case they were exposed to high volumes of aerobic work, they adapted themselves to the training response. Unfortunately for the strength and power fanatics out there, the reverse is not true- slow twitch fibers do not take on fast-twitch fibers properties if the strength training volume is high. In other words, if you want to perform well in sprinting, you better have chosen the right parents and be born with a greater than normal percentage of fast-twitch fibers.
Another possible mechanism for your slow gains in strength is that when one does slow cyclical type activities, the brain tends to organized contractions in that manner. In other words, it is hard for the brain to do ballistic high force contractions. A Japanese study done a few years ago showed that the more you increase your V02 max. the more your vertical jump actually decreases. A Finnish study showed that doing aerobic work for the upper body made your legs slower, showing that the negative power adaptation did not come from the muscles itself but from the nervous system.
Doing excessive amounts of aerobic work has been shown to lower testosterone counts and raise cortisol levels. However, normal testosterone production can return in no time providing that nutrition is optimal particularly the trace elements.
The good news are that there is evidence that upon cessation of doing aerobic work the fast-twitch fibers return to their original form. That is why long distance swimmers who stop training, increase their vertical jump by 4 inches, that is without even training their vertical jump.
I had a client who was a former Tour de France cyclist, he weighed 154 lbs at just under 6 feet of height. After nine months of doing only strength training, his bodyweight climbed to 192 lbs, but the gains in size, though appreciable, were very slow for the first six months. But at the sixth month mark, he started to grow like a weed, particularly after he dramatically increased his protein intake. In my opinion, it takes about 4 to 8 months to detrain the aerobic effect.
Be patient, the gains should come sooner or later.