Man setting up a barbell back squat in a rack

Leg Day Routine: Which Exercises Grow Which Muscles

9 min read

A good leg day gives every major leg muscle enough hard work to get bigger and stronger. In the MRI trials below, no single lift covered all of them. In a 10-week squat trial, the knee extensors, adductors and glutes grew, but the rectus femoris, one of the four quadriceps muscles, and the hamstrings did not change.

This guide uses trials that measured muscle size with MRI to show what squats, hip thrusts and leg curls each add, then sets out how many sets the research supports and two training-day templates. Most of these trials were small, so treat the findings as strong pointers rather than final answers.

+6.7%
Gluteus maximus volume after 10 weeks of full squats
Kubo et al. 2019, 8 men
+2.2%
Gluteus maximus volume after 10 weeks of half squats
Kubo et al. 2019, 9 men
+14%
Whole hamstrings volume after 12 weeks of seated leg curls
Maeo et al. 2021, 20 adults
+9%
Whole hamstrings volume after 12 weeks of lying leg curls
Maeo et al. 2021, 20 adults
Sources: Kubo et al. 2019, European Journal of Applied Physiology. Maeo et al. 2021, Medicine and Science in Sports and Exercise. Both measured muscle volume with MRI.

Squats: go deep

In 2019, Keitaro Kubo and colleagues at the University of Tokyo randomly assigned 17 men to full squats (8 men) or half squats (9 men), twice a week for 10 weeks. The knee extensors, the quadriceps group, grew by 4.9% after full squats and 4.6% after half squats. The adductors grew by 6.2% after full squats against 2.7% after half squats, and the gluteus maximus by 6.7% against 2.2%. Both differences were statistically significant.

Muscle growth after 10 weeks of squats Percent increase in MRI muscle volume, full squat versus half squat Full squat Half squat 4.9 4.6 Knee extensors 6.2 2.7 Adductors 6.7 2.2 Gluteus maximus Rectus femoris and hamstrings: no change in either group
Source: Kubo et al. 2019, European Journal of Applied Physiology. 17 men randomised to full squats (8) or half squats (9), twice a week for 10 weeks. Knee extensors are the quadriceps group. Values are mean percent increases.

Strength gains depended on the depth tested. Full-squat 1RM, the most weight lifted for one repetition, rose by 31.8% in the full-squat group and 11.3% in the half-squat group. Half-squat 1RM rose in both groups with no significant difference. The authors concluded full squats were more effective for developing the lower-limb muscles, excluding the rectus femoris and the hamstrings, which did not grow in either group.

Hip thrust or squat for the glutes

A 2023 trial by Daniel Plotkin and colleagues at Auburn University compared the two directly. It randomised 34 untrained college-aged adults to back squats (16) or hip thrusts (18), with the number of sets equal, for 9 weeks of supervised training. MRI showed comparable glute growth in the two groups. The squat group gained more in the quadriceps and adductors.

The hip thrust produced greater glute muscle activity in the first session, but that activity did not consistently predict glute growth. Strength gains matched the exercise trained: squat strength favoured the squat group and hip thrust strength favoured the hip thrust group. Deadlift strength improved by about the same amount in each group. The hamstrings showed little to no growth with either exercise.

Hamstrings need their own exercise

Neither the Kubo nor the Plotkin trial found meaningful hamstring growth from squats or hip thrusts. A 2021 study led by Sumiaki Maeo at Ritsumeikan University in Japan looked at a direct hamstring exercise. Twenty healthy adults trained one leg with seated leg curls and the other with lying (prone) leg curls: 5 sets of 10 repetitions at 70% of 1RM, twice a week for 12 weeks.

Hamstring growth, seated versus lying leg curls Percent increase in MRI muscle volume after 12 weeks Whole, seated 14 Whole, lying 9 Short head, seated 10 Short head, lying 9
Source: Maeo et al. 2021, Medicine and Science in Sports and Exercise. 20 healthy adults, one leg per method. The short head of the biceps femoris is the one hamstring muscle that crosses only the knee. Values are percent increases.

The whole hamstrings grew by 14% with seated curls against 9% with lying curls. The extra growth came from the hamstring muscles that cross both the hip and the knee. The short head of the biceps femoris, which crosses only the knee, showed no meaningful difference between methods. Sitting places the hamstring muscles that cross both joints at a longer length, and the authors suggested training at long muscle lengths promotes growth. This is one trial of 20 people, but it favours the seated version, so our templates use it.

How many sets, and how often

A 2017 meta-analysis by Brad Schoenfeld and colleagues pooled 15 studies and found a graded dose-response: each additional weekly set was linked to a 0.37% larger gain in muscle size. Grouping studies into fewer than 5, 5 to 9, and 10 or more sets per muscle per week showed only a trend that fell short of statistical significance.

A larger analysis by Joshua Pelland and colleagues at Florida Atlantic University, published in late 2025, pooled 67 studies with 2,058 participants. More weekly sets meant more muscle growth and more strength, with diminishing returns, and the returns flattened sooner for strength. For muscle growth, the frequency data were compatible with a negligible effect, while more frequent training increased strength gains. Our templates use two leg sessions a week, which spreads the sets across the week.

Two leg days: a template

The templates below are our coaching suggestion, built on the trials above. Across the two days, the quadriceps and glutes each get 10 or more hard sets a week, and the hamstrings get 6 sets of seated leg curls plus 4 sets of Romanian deadlifts. No cited trial measured hamstring growth from Romanian deadlifts, so the seated curl carries the direct hamstring work. Day A starts with a deep squat, and Day B starts with a Romanian deadlift followed by a hip thrust. Kubo found no rectus femoris growth from squats, so Day A adds a leg extension, which moves only the knee. No trial here tested whether that fills the gap. Calf raises are our addition, as none of these trials measured the calves. End each set when you could still complete two or three more repetitions, and add load or repetitions over time.

DAY A
Squat-led
Back squat or goblet squat, full depth: 4 sets of 6-10
Bulgarian split squat: 3 sets of 8-12 per leg
Seated leg curl: 3 sets of 10-12
Leg extension: 3 sets of 10-15
Standing calf raise: 3 sets of 10-15
DAY B
Hinge-led
Romanian deadlift: 4 sets of 6-10
Barbell hip thrust: 3 sets of 8-12
Leg press, deep range: 3 sets of 10-12
Seated leg curl: 3 sets of 10-12
Seated calf raise: 3 sets of 12-15

If you are new to lifting, our suggestion is to start with two sets of each exercise, use dumbbells for the squat and Romanian deadlift, and build up to the full sets over four to six weeks. Rest at least a day between the two sessions. Warm up with lighter sets of each main lift. Set the rack safety arms at the bottom of your squat, keep a neutral spine on the Romanian deadlift, and use a bar pad for hip thrusts. Stop any exercise that causes sharp pain, and see a GP or physiotherapist if pain persists. The NHS asks adults to do strengthening activities that work all the major muscle groups on at least 2 days a week, taken to the point where you need a short rest before repeating. Speak to your GP first if you have not exercised for some time or if you have medical conditions or concerns.

Common mistakes

  • Cutting squats short. In the Kubo trial of 17 men, half squats grew the glutes and adductors less than full squats.
  • Expecting squats to build the hamstrings. Squats and hip thrusts produced little to no hamstring growth in the trials above, so add a direct hamstring exercise.
  • Choosing exercises by muscle activity alone. In the Plotkin trial, higher glute activity in the hip thrust did not consistently predict more glute growth.
  • Doing too few sets. Both volume meta-analyses linked more weekly sets with more growth, and the 2025 analysis found diminishing returns.

Frequently asked questions

How many leg days a week should I do?
The NHS asks for strengthening activities that work all the major muscle groups on at least 2 days a week. In a 2025 analysis of 67 studies, the frequency data for muscle growth were compatible with a negligible effect, while more frequent training increased strength. Our templates use two sessions a week to spread the sets.
Are hip thrusts better than squats for the glutes?
In a 9-week trial in untrained adults, hip thrusts and squats produced similar glute growth. The squat group also gained more in the quadriceps and adductors. Each built more strength in the exercise trained.
Do squats work the hamstrings?
In the Kubo trial, hamstring volume did not change after 10 weeks of full or half squats. The Plotkin trial found little to no hamstring growth from squats or hip thrusts. A leg curl trains them directly.
Seated or lying leg curl?
In a 12-week trial in 20 adults, seated curls grew the whole hamstrings by 14% against 9% for lying curls. The authors linked the difference to training the hamstrings at a longer length.
How many sets per week do legs need?
A 2017 meta-analysis linked each extra weekly set with slightly more growth. A 2025 analysis of 67 studies linked more sets with more size and strength, with diminishing returns.

The bottom line

In small MRI trials, deep squats grew the knee extensors, adductors and glutes, hip thrusts matched squats for glute growth, and neither produced meaningful hamstring growth. Seated leg curls grew the hamstrings more than lying curls. More weekly sets were linked to more growth, with diminishing returns. Our templates build two leg days around a deep squat, a Romanian deadlift, a hip thrust, a seated leg curl and a leg extension. Add load or repetitions over time.

Get a leg programme built for you
DT Fitness London coaches squat, hinge and hip thrust technique one to one and sets your weekly volume around your level and schedule.
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Related reading

Sources

  • Kubo K, Ikebukuro T, Yata H. Effects of squat training with different depths on lower limb muscle volumes. European Journal of Applied Physiology 2019. pubmed.ncbi.nlm.nih.gov/31230110
  • Plotkin DL, Rodas MA, et al. Hip thrust and back squat training elicit similar gluteus muscle hypertrophy and transfer similarly to the deadlift. Frontiers in Physiology 2023. pubmed.ncbi.nlm.nih.gov/37877099
  • Maeo S, Huang M, et al. Greater hamstrings muscle hypertrophy but similar damage protection after training at long versus short muscle lengths. Medicine and Science in Sports and Exercise 2021. pubmed.ncbi.nlm.nih.gov/33009197
  • Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis. Journal of Sports Sciences 2017. pubmed.ncbi.nlm.nih.gov/27433992
  • Pelland JC, Remmert JF, et al. The resistance training dose response: meta-regressions exploring the effects of weekly volume and frequency on muscle hypertrophy and strength gains. Sports Medicine 2026, published online 2025. pubmed.ncbi.nlm.nih.gov/41343037
  • NHS. Physical activity guidelines for adults aged 19 to 64. nhs.uk/live-well/exercise/physical-activity-guidelines-for-adults-aged-19-to-64
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