"What's the Difference Between Lower Weight with Higher Reps, And Higher Weight with Lower Reps?"

I LOVE this question! The person that asks this question shows that s/he isn't just going through the motions, and they're really interested in what they're doing inside the gym.

I'll start by giving a simplified anatomy/physiology lesson. Muscles are comprised of 2 different types of muscle fibers. Slow twitch and fast twitch. Slow twich fibers are more for endurance/volume types of workouts (Long runs/rows, reps higher than 10-15). Fast twitch fibers are more for quick/explosive movements (1RMs, sprints, max jump heights, etc).

When you workout with lower weight, and higher reps, you're using energy systems that adapt the slow twict fibers. The opposite goes for fast twitch.

Now comes the potential bummer. Humans are born with the ratio of slow to fast twitch fibers that they'll always have. So, you may be really good at gaining strength and adding weight to your 1RMs, but really struggle with getting better at longer workouts or 10+ rep max's. Again, the opposite is true for slow twitch.

What does this mean for which types of workouts you should be choosing? It still comes down to what your fitness goals are. If you're the type of athlete that wants to get stronger, then choose heavier weight and lower reps. But, if you're the kind of person that has a hard time getting stronger, then you'll have to be ok with it taking a little bit longer than others, and/or really dial in nutrition to hit those goals.

The human condition tends to lead us towards what we're good at. Think about all the times you've seen people during open gym. The majority of the time, strong people like to keep lifting heavy weights, and endurance bunnies like to do MetCon's (this is generally speaking). If you're having a hard time reaching your weight training goals, it may take a little bit of self-awareness and patience.

The great thing about CrossFit is that we cover the gambit of training ranges. Whether you like light or heavy weight, you'll see both in a well balanced training program.