Hitting the gym can help with your endurance riding as the others have suggested.
A few things I have found to assist are:
- Strengthening the arms (triceps), back and shoulders helps with seeing out endurance events.
- Protein powders are to be used as supplements and are not the solution. If you are using them - stick to a low fat whey protein or sustagen sport - but a balanced diet is generally better and cheaper. If using a protein powder - you get what you pay for. I find cheap powders don't get along too well with my stomach.
- Gym work takes time to have a positive effect on your riding
- Time on the bike will generally be of more benefit than time in the gym and provides results quicker!
Good luck
That is one of the woes of cheap protien powders.
The first one is that the concentration is lower, when it says 100% whey it does not mean that you get 100%pure whey. Divide the serve size by the protien per serve to get the percentage. You pay more for higher protien because they contain less concentrate and more isolates.
The second one is the digestion, due to lower processing they can give people digestive issues. Look for Hydrolyzed and different protien sources ie egg protien, rice, pea etc.
Hydrolyzed is basically designed to be somewhat predigested, they do enter the system faster but it is so negligable it's not worth the cost for that reason alone, I would personally only my bother to help prevent stomach issues.
I would advise against soy for men due to its ability to raise estrogen.
As for your final suggestion about on the bike provides more benefit I would be cautious with that, for new riders and people who are not conditioned to riding, riding Lone can and yield good results though there is a point where certain muscles and the body needs more load to improve this is where gym work comes in. You can't isolate or stress the muscles on the bike adequately once you reach a certain level, off the gym helps strength and can help focus on specific weakened areas.