If you're over 40 or will be someday, you need to fight back against the slow erosion of time. There are guys 20 years older than me who can beat me without breaking a sweat. But now I know their secrets.

My last bike tour crippled me.

I was fighting a strong headwind for most of the first day, and when the weather improved I didn’t. My left knee was swollen and sounded like a blender full of ice cubes. I turned back less than halfway through the tour, and I took a bus the last ten miles back home because it hurt too much to ride.

I’m better now, but this trip was my first sign of middle age. Although it’s not just about the years (or even the mileage).

I know a lot of people 20 years older than I am, who could ride circles around me all day and wake up ready to do it again tomorrow. I want to be like them, and now I've learned their secrets.

I’m writing this because you might be in the same situation. If not today, then someday…

For my birthbike tour california mountainday, my wife bought me Roy Wallack’s book, Bike For Life: How to ride to 100--and beyond. If I had read this book a year ago, I wouldn’t have been defeated on my tour. The chapter on knee pain taught me how to fix my problem in less than a month.

I’m not going to give away all of Roy’s secrets. There are some tools, techniques and exercises in this book that haven’t been discussed anywhere else that I’m aware of. But there are some very useful concepts I think you should know about.

The biggest take-away was the importance of maintaining your fast-twitch muscles as you get older. These muscles are the first to go, and that’s a big part of the reason old people lose their balance, coordination, and reflexes.

(For a quick primer on fast-twitch and slow-twitch muscles, check out this BBC article.)

You build fast-twitch muscle fibers by lifting very heavy weights. There’s a science to this, and a specific way to do it,* which he explains in detail in the book. I had never done this kind of exercise before. It’s been a game-changer for me after just a few weeks.

Roy Wallack also reminds you that you have a life off the bike as well as on it. Bike for Life teaches you a handful of critical exercises that reverse the damage caused by cycling. (Yes, riding a bike can be bad for you, just like too much of anything) Your posture and your back muscles need extra attention.

The flip side is that everyday life tears down your body in ways that make you weaker and slower on the bike. Bike for Life has 10 longevity stretches and another set of exercises that make you stronger and faster.

This book is packed with a ton of other great tips that I can’t get into here: Yoga routines that help your biking, detailed workout plans designed to put you at your peak for a ride or race on a specific date months in the future, tips on attacking hills and a lot more.

Roy also implies that you shouldn’t take his advice as absolute truth. Throughout the book he interviews “mature” cyclists who sometimes win races by doing the exact opposite of what he suggests. He’s also candid about his own embarrassing mistakes.

Early on, the book recommends that nobody over 40 should ever go on a bike tour. I’ve already broken that rule many times, and I intend to do so for decades to come.

Thanks to this book, I’ll be able to.

*Disclaimer: This article is for informational purposes only and is not intended to provide medical advice. This information is not intended to diagnose, prevent, treat, or cure any disease. The activities described are potentially dangerous. Consult a physician before engaging in any kind of exercise regimen.