The often-discussed topic of how to lift weights properly generally ends up with a conclusion along the lines of: what we should be doing is observing how the athlete will be moving during their activity, and then devising a plan to mimic that with weightlifting. This is when you’ll see runners grabbing ridiculously light weights and performing carefully choreographed single-leg movements at a high volume to attempt to train in a way that is similar to how they will be running. Not only does it look ridiculous, but it’s not providing a stimulus that triggers the adaptations that we should want from strength training in the first place.
If you want your strength training routine to “mimic” running, forget what you’re doing and go run instead. The purpose of strength training should be entirely different than the purpose of running in terms of adaptations to training, so when you attempt to meld the two, you’re likely removing the main benefits of each and coming up with an entirely new and mostly useless concoction.
This idea, in my opinion, would be similar to mixing together steak and ice cream — both are fantastic on their own, but blend a steak up and make ice cream with it, you’re probably ruining both ideas (though to be fair, I have never tried this and could easily be wrong here).
What we want to look at with regard to strength training is the way in which different methods (movements, loading, rep scheme) of lifting affect different muscle fiber types and neurological improvements in strength/power/control. After all, strength training is unlikely to be an important way to specifically improve your endurance, and so should be used to affect strength and muscle composition. Get your endurance from endurance training, use strength training to build your foundation. Strength training for the purpose of getting stronger will improve your endurance performance, but in a way that is different than the way in which endurance training improves your endurance performance.
So how should we lift weights?
An interesting paper that I stumbled upon was looking at the muscle-fiber composition of powerlifters, which brought some interesting information to me.
In this post I explained why I feel type IIa muscle fibers would be beneficial for endurance, even though “endurance athletes” are often characterized predominantly as “slow-twitch” type I athletes. Taken from that post:
Type I muscle fibers have lots of mitochondria, a great capacity to store triglyceride (storage form of fatty acids), and a very high oxidative capacity. They are the most fatigue-resistant muscle fiber.
Type IIa muscle fibers have a decent amount of mitochondria as well, a much larger capacity for glycogen storage, and a relatively high oxidative capacity. They are very fatigue-resistant and can produce high amounts of force.
Now, let’s have a look at what the muscle fiber composition of competitive powerlifters looks like, (source)
This is powerlifter muscle.
You’ll notice that the powerlifter muscle is made up of large amounts of both of the fiber-types that would be beneficial for endurance performance. This is what we want — muscle that can produce force, has fatigue resistance, and can efficiently utilize fuel substrates. We should look to develop a similar profile as endurance athletes, only we will train and use the muscle differently afterward.
Lifting heavy weights with a varying volume (but still relatively low compared with conventional recommendations) dependent on the specifics of your training program will provide the stimulus required to create this muscle composition.
The 2 main movements that would yield specific benefits for running or cycling (though I would suggest upper body strength and stability to be beneficial as well) would be squatting and deadlifting. These are multi-joint movements that recruit muscles from many areas in order to stabilize and move you through the lift. In essence, they are basic human movement patterns that should be strengthened and adapted for your needs.
Strength training should be the foundation of your training, for building the type of muscle and strength that would be beneficial for you.
Powerlifters have a muscle fiber makeup that would be beneficial to endurance athletes, at least to some extent.
You should take note and lift heavy things for your strength training — loading and volume will depend on where you are in your program.
Basic human movement patterns, like the Squat or Deadlift, are fantastic movements to include in your training.