Strength training is controversial when we discuss optimizing training programs for cyclists. There is no definitive answer to whether cyclists should include weight lifting in their winter training plans. Several studies are unsuccessful in proving that cyclists can benefit from strength training.
One of the biggest problems for these scientific studies is that they include untrained cyclists, and the study group is usually small. That makes it rather difficult to prove a significant difference between endurance training only versus endurance training combined with weight lifting.
My best guess is that strength training does make a difference, and it is, at least in theory, possible to prove it with a larger study group. But the difference between including strength training or not is not the most critical factor in overall performance in road races.
Thus, it isn’t straightforward to recommend going to the gym or spending an extra hour on the bike. However, you will probably improve your overall performance level in both cases. It is essential to notice that even though studies about strength training do not produce significant gains in overall cycling performance, there is very likely a difference.
As I wrote in a previous post about strength training, many cycling coaches do not know what they are doing in the weight lifting gym. It seems like they are trying to convert their training principles from the cycling world into the weight lifting world. I believe that cycling coaches should listen to people who are more experienced with developing explosive power.
Track and field coaches have a very scientific approach to strength training. Olympic-style weight lifters are experts at improving power without gaining additional bodyweight. As a result, knowledge about strength training increases at a very accelerated pace, but most riders stick to their conservative training principles. I hope that more riders and coaches will open their eyes and discover what is going on.