Leg day is like going to the dentist – everyone knows we should do it, but yet we all hate it.
Because training legs is hard.
Much harder than sets of 10 on the bench press or supersets of hammer curls and skull crushers.
Leg day requires mental fortitude and exceedingly high pain tolerance.
Most lower body work tends to turn into a full-body endeavor. Anyone who has pulled a deadlift 1-RM (aka one-rep max) will be the first to tell you that lower body training is brutally difficult.
As a result, you’ll find numerous people who continue to skip leg training. They often dedicate an entire 90-minute training session to each individual body part. But they continue to avoid legs because they dislike squats and deadlifts.
Now, don’t get me wrong … squats and deadlifts completely wipe out even the most-seasoned lifter. This is simply the nature of the lift. But just because something is difficult isn’t a good reason to avoid it.
Not only that, training legs is supported by science for several valid reasons. It’s time to set your personal biases aside and objectively examine the facts.
Use Leg Day to Expedite Muscular Growth
Most people associate leg training with hypertrophy of the calves, quads, hamstrings, and glutes. However, most trainees forget the level of activation and subsequent growth of their core and back, which comes from well-executed leg training.
If you’ve ever studied or trained lifters who deadlift and squat 400+ pounds routinely, you know about their impressive mid and upper-back development. While this can certainly be the result of countless rows and pull-ups, it’s usually due to the excessive loading that the back endures during deadlifts.
Bottom Line: When you see a pair of thick spinal erectors and well-formed traps outlining the back of a t-shirt, you can be sure that that individual trains their legs hard, and their back reaped the benefits.
Sport-Specific Considerations for Leg Day
I’m going to be blunt. If you’re an athlete or anyone who enjoys playing sports at any level, you absolutely must show up for leg day and train your lower body by focusing on progressive overload.
There is no getting around this point. The best athletes in their respective sports have exceptionally strong lower bodies and great core control of their pelvis.
You often hear people exclaim, “Wow, that person has fast feet.”
That’s a misnomer. You only get fast feet from strong hips, and you only get strong hips from lifting weights.
In actuality, the saying should be, “Man, that person has quick hips.”
As legendary hockey coach Herb Brooks says, “The legs feed the wolf.”
Even if you play a fairly upper body “dominant” sport (aka golf, tennis, baseball), keep in mind that all your rotational power is built from the ground up.
Watch the best players when they try to generate speed within a rotation. They actually move through a mini jump or hop (aka hip extension) as they reach the peak point of impact where they release all the force they’re creating.
When I was working with the head of biomechanics for the Olympic training site, we would often get golfers set up on force plates to look at the rate of force development (RFD), weight distribution, and peak power output (PPO).
New golfers often lacked the ability to generate force because they didn’t understand how to drive into the ground and create tension. They would often overswing with their upper body and lose power by trying to overcompensate for a weak core and hips.
As they lifted over the competitive season, we found that nearly all golfers (regardless of age, gender, experience, and skill level) improved their RFD and PPO in both their swing and in the weight room. The sport-specific transfer was nearly undeniable. We examined the data, and the results spoke for themselves. We saw longer drives, smoother transitions, better balance, and lower scores.
Bottom Line: If you’re an athlete who regularly avoids leg day, you will never reach your maximum potential.
When it comes to losing fat, there’s generally one key principle that greatly enhances (or detracts) from one’s ability to succeed – the total work (aka volume) completed with maximal muscular activation.
Let’s start with the following physics formula:
Work (W) = Force (F) x Distance (D)
The formula for energy is related but slightly different:
Energy (E) = Work (W) + Heat (Q)
Now if you combine both those formulas by subbing in the force and distance for work in the second equation, we have the following:
Energy (E) = Force (F) x Distance (D) + Heat (Q)
Thus, an individual’s total energy is a direct result of the force required to move a specific mass a certain distance. This produces heat as a byproduct (aka why you sweat when you lift).
Leg training is the fastest way to drive up the force value of this equation. On leg day, complete 1 set of 20 back squats. Then, follow that up with 1 set of 20 on a machine chest press. Report back with how hard you’re breathing after each set and how long it took you to recover.
If you’re like most, you probably won’t make it to the chest work. You’ll be lying on the floor for 5 minutes, trying to figure out where all the oxygen in the room went.
Bottom Line: Lower body work is grueling but necessary. This is especially true if you’re looking to burn fat and build muscle. When you’re in a calorie deficit, trying to lose fat, and skipping leg day, there is a 100% chance you will lose muscle from your lower body. It’s not a question of ‘if’ but ‘when.’
Late-Stage Muscle Mass Retention
If you’re young, this point may seem completely irrelevant. But eventually, you will grow older, and this will become exceptionally relevant. It may even save your life.
As we age, we must keep in mind two key determinants of strength and function: muscle mass and grip strength. Both are likely the strongest predictors of all-cause mortality and life expectancy.
“Grip strength was an independent predictor of all-cause mortality and cardiovascular diseases in community-dwelling populations.” — Wu et al., 2017
“At any level of BMI ≥22, participants with low muscle mass had higher body fat percentage (%TBF), an increased likelihood of diabetes, and higher adjusted mortality than other participants. Muscle mass mediates associations of BMI with adiposity and mortality and is inversely associated with the risk of death.” — Abramowitz et al., 2018
What does all this even mean, and why does it matter when it comes to skipping leg day?
The older we get, the weaker we get, the fatter we get, and the higher our chances of death (aka mortality in scientific terms).
If you’re in your 20s or 30s, this may seem preposterous. Keep in mind that the training you complete today sets the stage for the next two to three decades. These are your prime years of growth. If you choose to waste them and not accrue as much muscle mass as possible (especially in your legs), you will have a hard time catching up later in life.
Muscle also acts as a form of ‘body armor.’ If you fall, you have a lower chance of fracturing a bone, tearing a tendon/ligament, or producing significant bodily harm. However, those with low muscle mass (especially in their lower body) tend to struggle with fractures after a fall. And, they usually have a harder time acclimating back to a normal lifestyle later in life.
Bottom Line: Build muscle now so that you won’t have to worry about later. Later in life, the process becomes exponentially more difficult.
Long-Term Injury Prevention
This will become painfully relevant to many lifters over the course of their career (myself included).
For activity-related injuries, most people will suffer some non-contact injury to their lower body as opposed to a wrist, elbow, or shoulder. While shoulders can sometimes be problematic, ACLs, menisci, and lower body tendons are much more of an issue.
Take me, for example. I ruptured an Achilles tendon a little over 2 years ago when playing baseball at the age of 26. I was in the prime of life and quite strong, squatting almost 2x my bodyweight and deadlifting 450+ pounds regularly. In fact, I was in the middle of an especially intense training block as part of a Russian squat program called Smolov.
But I failed to take my own advice. I didn’t train and prepare for the sport I was playing. I merely squatted and deadlifted heavy but didn’t take the time to do the little things. In my case, that would have been more plyometric and elastic work on my ankles – hops, skips, and jumping rope. As a result, I paid the price and have been on the long road to recovery ever since.
And the same is true for you. As you age, you’re going to be fighting age-related muscle loss (sarcopenia). This weakness will result in a higher tendency for a variety of issues. However, muscle and tendon-related complications are usually quite high in non-lifting populations.
Bottom Line: Don’t let your lack of leg training early in life be the reason you’re forced to have ACL surgery before you’re 30 or an arthroscopic “clean out” on your 40th birthday. Train hard now, and save yourself the surgery later.
Whether you’re new in your fitness journey or you’ve been training for multiple decades, regularly including leg day in your rotation keeps you healthy, fit, and injury-free throughout your training career.