A good single leg workout does most of its work one leg at a time, through a squat, a lunge and a press, and still covers calves and hamstrings. For muscle, the research can't tell it apart from two-legged training: a 2025 meta-analysis of 9 studies found no significant difference in growth between the two. Strength is where they split: you get stronger at the version you train. Here's the six-move day I run, in order: a front-rack kettlebell Cossack squat, a four-way lunge with a press, a single-leg press, a Smith machine Bulgarian split squat, an incline-wedge calf raise, and a deficit RDL.
I'm 37, a full-time software engineer, and I lift four days a week. I posted this leg day as a reel and called it what it is: primarily single-legged. Below is what each move is for, the cue that matters on each, and the research on the two big claims for single-leg work. One holds up. The other is weaker than the internet makes it.
What is a good single leg workout?
It's a leg day that covers hips to calves, with most of the work done one leg at a time. Here's mine, with my reason for each move and the cue I'd give you.
1. Front-rack kettlebell Cossack squat
I start here, with two kettlebells held in the front rack. It feels really good on the hips, and it's a good core challenge. A Cossack squat is a wide-stance squat to one side: sit over one leg while the other stays straight, then shift across. I couldn't find a trial on it, so this is coaching opinion: it works the hips through a side-to-side range most leg days never touch, which makes it a good opener.
The cue: keep the heel of the bent leg flat, and only go as deep as that heel allows. Keep the bells high on your chest with the elbows tucked. The weight pulls you forward, and your trunk has to hold you upright.
2. Four-way lunge with a press
Next come four-way lunges, and I press at the bottom of each lunge. That's a little upper-body work and another good core challenge. A four-way lunge cycles one leg through four directions, usually forward, to the side, back, and a diagonal step behind. The press is a light weight pushed overhead at the bottom of each rep, then lowered before you stand.
The cue: freeze the bottom position while you press. If your torso tips or your front knee caves as the weight goes up, the weight is too heavy for this move.
3. Single-leg press
Then single-leg presses. My reason for this one is in the reel word for word: "just trying to even out the imbalances between legs." The sled takes balance out of the move, so each leg moves the weight with no help from the other.
The cue: put your foot in the middle of the platform. Stop the descent before your hips curl off the pad. Start with the weaker leg, then do the same reps on the stronger one.
4. Smith machine Bulgarian split squat
Then Bulgarians. They're brutal, and I love them on the Smith machine because you can really load them heavy. The fixed bar path takes the wobble out, so your leg gives out before your balance does. Your back foot goes on a bench behind you.
The cue: most of your weight goes through the front heel. The back leg is a kickstand. Drop the back knee straight down toward the floor, not forward.
5. Incline-wedge calf raise
Second to last: calf raises on an incline wedge. It really gives you a deep stretch. With your toes up on the wedge, every rep starts from a lengthened calf.
The cue: pause for a full second at the bottom, heels as low as they go, and don't bounce out of it. The bottom of this rep is the part the research favors (more on why below).
6. Deficit RDL
I finish with deficit RDLs, and the stretch on these is crazy. You stand on a plate or a low step, so the weight can travel lower and the hamstrings work through a longer range.
The cue: the deficit only counts if your back stays flat. Push your hips back and keep the weight against your legs. Stop when your hamstrings are fully stretched, not when the weight touches your shoes.
Is unilateral leg training better than squats?
For muscle, the research shows no winner. For strength, the winner is whichever version you train.
The best summary is Kassiano and colleagues' 2025 meta-analysis in Sports Medicine. Of 703 studies screened, 9 made the cut. Muscle growth showed no significant difference between one-leg and two-leg training (effect size β0.21, p = 0.57). Strength followed specificity: two-leg training built more two-leg strength (effect size 0.56), and one-leg training built more one-leg strength (0.65). The authors call the literature limited, the studies carry moderate risk of bias, and the confidence interval on growth is wide. Read it as "no evidence either one builds more muscle," not "proven identical."
The direct test is small but clean. Speirs and colleagues (2016) split 18 academy rugby players into two groups for 5 weeks, twice a week. One group did only rear-foot-elevated split squats. The other did only back squats. Both groups improved their back squat max, their split squat max, their 40 m sprint and their agility time, with no significant difference between the groups. The split-squat group never back squatted in training and still kept pace on the back squat.
Liao and colleagues' 2022 meta-analysis in Biology of Sport pooled 14 studies and 392 participants aged 16 to 26. Two-leg training won on two-leg strength (effect size 0.43), one-leg training won on single-leg jumps (0.89), and nothing else reached significance.
So pick the version you can load hard and keep progressing. If barbell squats bother your knees or back, the research shows no size cost to a single-leg day. If only the back squat bothers you, the front squat is the other way out: about the same quad work with a lighter bar and less compressive force on the knee (front squat vs back squat has the studies). Everything else about how to build bigger legs still applies: add load over time, and train quads, hamstrings and calves, not just the parts you see in the mirror.
Do single leg exercises fix muscle imbalances?
They show you the imbalance and let you train each side to the same standard. The evidence that the imbalance was hurting you is weaker than most coaches suggest.
Evening out my legs is the exact reason the single-leg press is in this day. On a two-legged lift, the stronger side can take more of the load, and the number on the bar won't tell you. On one leg, each side has to move the weight by itself.
Here's the limit. Helme and colleagues' 2021 systematic review in Physical Therapy in Sport covered 31 papers and 6,228 athletes. Twenty found at least a partial link between leg asymmetry and injury, but the authors rated the evidence moderate to lower quality. Their verdict: a link can't be ruled out. That's a long way from proven. My view is that asymmetries are where knee and hip problems tend to start. That's an opinion, not a finding.
The "bilateral deficit," where each leg makes less force in a two-leg effort than on its own, is shaky too. A 2016 review by Ε karabot and colleagues found it inconsistent, sometimes reversed, and barely studied against performance or injury.
Single-leg strength and balance are also separate qualities. A machine single-leg press trains the first and barely touches the second. If balance is the goal, how long you should be able to stand on one leg is a different test with its own norms.
Do deep-stretch exercises build more muscle?
Training at long muscle lengths seems to grow some muscles more. "Stretch equals growth" goes further than the data does. That's the case for the last two moves.
On calves, Kassiano and colleagues (2023) put 42 young women through 8 weeks of calf raises, 3 days a week: full range, bottom half only (the stretched part), or top half only. The bottom-half group grew the inner calf 15.2%, against 6.7% for full range and 3.4% for the top half. On the outer calf it beat the top half (14.9% vs 6.2%) but not full range (7.3%) by a significant margin. That's one 8-week study in young women, so I wouldn't drop the top half on it. I would never cut the bottom short.
On hamstrings, Maeo and colleagues (2021) had 20 adults train one leg on a seated leg curl and the other on a lying curl for 12 weeks. Sitting puts the hamstrings at a longer length. Whole-hamstring volume grew 14% on the seated leg against 9% on the lying leg. The muscles that cross both the hip and the knee drove the difference. The one that crosses only the knee grew about the same either way.
An RDL loads the hamstrings at long lengths, and the deficit adds range at the bottom. But I couldn't find a trial on deficit RDLs or incline-wedge calf raises; the research tested long muscle lengths, not these exact moves. Own the bottom of both, and don't bounce.
How many sets and reps should a single leg workout be?
Do 2β3 hard sets of 8β12 reps (per leg on the one-leg moves), and stop each set 1β2 reps short of failure. Calves can run higher, 12β20. That's the prescription, not a log of my reel. Two or three hard sets beat four sets of junk volume.
The real cost is time. Per-leg sets roughly double your working time, because three sets of Bulgarians is really six. Rough math at 2-minute rests: four single-leg moves at 3 sets per leg take about 40 minutes, the two finishers about 15, warm-ups about 10. That's 65 minutes, or closer to 50 at 2 sets per leg. Either way it fits the 45β75 minutes that how long a workout should be works out to.
Six moves sits at the top of the four to six exercises per workout that most sessions need. If the clock is tight, cut sets before you cut moves, and keep the Bulgarians at full sets.
How do you add a single leg day to a 4-day split?
Swap it in for your leg day. In push, pull, legs, upper, this becomes the legs session and nothing else changes. That's the four-day split I run, and it gives legs one hard session a week, so make it count. That's a trade, not a rule: if legs are your priority, turn upper day into a second leg day.
Then progress the load. The Smith machine Bulgarian is the move to push, because you can load it heavy without balance as the limit. When every set hits 12 reps on both legs, add weight.
Log your reps per leg, not per set. The weaker side sets the pace. If your left leg gets 9 reps where your right gets 12, your next goal is 12 on the left, not more weight on the right. Track it, review it every session, and adjust when the weaker side stalls. That's the No-Guess Loop applied to a lift. You can't close a gap you never measured.
If you want the rest of the week laid out, my free 4-day starting routine covers push, pull, legs and upper, plus the daily scorecard. Its template leg day is built on two-legged lifts: squat, Romanian deadlift, leg press. Swap this day in, or at least put a Bulgarian split squat first in that session.