Squats and deadlifts together hit most of your leg musculature, but they leave a few notable gaps. The two lifts are excellent for building your quads, glutes, and the bulk of your posterior chain. For many people, especially beginners and intermediates, they form a solid foundation. But if your goal is complete leg development, a couple of muscles get shortchanged by this pairing alone.
What Squats and Deadlifts Actually Work
EMG research measuring muscle activation during both lifts shows a clear pattern: the quads and spinal erectors do the heaviest lifting, followed by the glutes and hamstrings. In one study comparing the two exercises at maximal effort, the vastus lateralis and rectus femoris (the outer and front portions of your quads) reached 97% to 105% of their maximum activation during back squats, and 104% to 105% during deadlifts. Glute activation reached around 72% to 80%, while the biceps femoris (the main hamstring muscle people think of) hit 78% to 82%.
That means both lifts are powerful quad builders, and both produce meaningful glute and hamstring activation. The overlap between them is real, but each exercise shifts the emphasis slightly. Squats load the quads through a deeper knee bend and challenge the glutes through a full range of hip flexion. Deadlifts emphasize the posterior chain more heavily from the floor, with the spinal erectors working hard throughout.
One muscle that gets quietly hammered by both lifts is the adductor magnus, the large inner thigh muscle. It’s actually the primary muscle initiating hip extension from a deep squat position, making it one of the most powerful contributors when you stand up out of the hole. Between squats and deadlifts, your adductors get substantial work.
Where Hamstring Coverage Falls Short
This is the biggest gap in a squat-and-deadlift-only approach. Your hamstrings cross two joints: the hip and the knee. Squats and deadlifts train them through hip extension (straightening your hips), but neither exercise involves significant knee flexion (bending your knee against resistance). That matters because the short head of the biceps femoris, one of the four hamstring muscles, only activates significantly during knee flexion. It barely participates in hip extension movements.
A systematic review of hamstring activation confirmed this directly: the elevated muscle response seen during leg curls compared to deadlifts was partly driven by the short head of the biceps femoris engaging in ways it simply doesn’t during pulling movements. The researchers emphasized that biarticular muscles (those crossing multiple joints) need to be trained through all their functions for complete development. For the hamstrings, that means you need both hip extension work and knee flexion work.
In practice, this means adding some form of leg curl. Seated leg curls, lying leg curls, Nordic hamstring curls, or a stability ball curl all fill this role. Without one of these, you’re leaving a portion of your hamstrings understimulated no matter how heavy you deadlift.
Calves and Hip Abductors Get Minimal Stimulus
Your calves act as stabilizers during squats and deadlifts, but they never move through a meaningful range of motion under load. If you care about calf size or strength, neither lift provides enough stimulus to drive growth. Standing or seated calf raises would need to be added separately.
The gluteus medius and minimus, the muscles on the side of your hip responsible for lateral stability, also get limited work from bilateral squats and deadlifts. These muscles fire hardest during single-leg movements, lateral movements, and exercises where you’re resisting your knee caving inward. Bilateral barbell lifts performed on two feet simply don’t challenge them in the same way. Single-leg exercises like lunges, Bulgarian split squats, or lateral band walks address this area more effectively.
Do You Need Isolation Work for Your Quads?
Probably not, unless you’re an advanced lifter chasing specific quad development. A meta-analysis published in the Strength and Conditioning Journal compared hypertrophy from programs using only multi-joint exercises (like squats and deadlifts) to programs that also included single-joint exercises (like leg extensions). The difference was trivial. This held true whether training volume was equated between groups or not.
For most people, squats alone provide enough quad stimulus to drive growth. The four heads of the quadriceps all activate strongly during squatting, particularly when you use a full range of motion. Leg extensions can be useful for targeting the rectus femoris specifically or for training around a back injury, but they aren’t necessary for building overall quad size if you’re already squatting consistently.
Recovery Is Manageable With Both Lifts
One concern people have about programming both squats and deadlifts is systemic fatigue. Heavy sessions of either lift are taxing, and stacking them can feel brutal. Research on well-trained men found that bar speed after heavy squat sessions remained depressed for up to 72 hours, while deadlifts surprisingly didn’t produce the same measurable decline. Overall, the deadlift did not result in greater muscle damage or longer recovery time than the squat in volume-matched training.
This suggests that programming both lifts in the same week is realistic for most trained individuals. Spacing them 48 to 72 hours apart, or placing them on separate training days, gives most people enough recovery. If you’re training legs twice per week, squatting on one day and deadlifting on the other is a common and effective split.
A Practical Recommendation
If you’re building a minimalist leg program, squats and deadlifts cover roughly 80% of the job. Your quads, glutes, adductors, and most of your hamstrings will grow. But two additions make the program meaningfully more complete:
- A knee flexion exercise like leg curls or Nordic curls, to target the short head of the biceps femoris and fully develop the hamstrings.
- A single-leg or lateral movement like Bulgarian split squats or lateral band walks, to load the hip abductors and improve single-leg stability.
Calves are a separate consideration entirely and depend on your goals. Some people’s calves grow from heavy squats and walking; others need direct calf work to see any change.
For a beginner or intermediate lifter who only has time for two leg exercises, squats and deadlifts are an excellent choice. They produce more total leg muscle activation than almost any other pairing. But “enough” depends on what you’re training for. If complete leg development is the goal, those two small additions close the remaining gaps without adding much time to your workouts.