Do squats work our hamstrings effectively?

Posted by Dayne Hudson in Muscle Building

Estimated reading time: 6mins

Do squats work our hamstrings effectively?

Squats for hamstring development

This study looked at front squats, full depth back squats, and parallel back squats, to see how the hamstrings were activated.

Here are these exercises below:

Front Squat Form
Front Squat Form
Full Squat Form
Full Squat Form
Parallel Squat Form
Parallel Squat Form

And in line with other research, the hamstrings didn't engage much at all during these exercises.

Take a look at the graph below: I've squared out in red the "biceps femoris" which is another term for hamstrings:

Mean ± SD of EMG (%MVIC) values in the parallel, full, and front squat.

ParallelFullFront
Mean
Upper gluteus maximus29.35 ± 16.4529.58 ± 16.2629.15 ± 14.35
Lower gluteus maximus45.29 ± 23.5442.24 ± 21.5143.89 ± 20.75
Biceps femoris14.92 ± 6.6414.39 ± 6.4113.11 ± 4.70
Vastus lateralis110.35 ± 47.24123.82 ± 67.42124.22 ± 72.96
Peak
Upper gluteus maximus84.85 ± 42.9188.13 ± 47.8384.62 ± 50.48
Lower gluteus maximus129.60 ± 60.45124.76 ± 55.44134.62 ± 55.71
Biceps femoris37.50 ± 18.3938.59 ± 16.8239.35 ± 22.79
Vastus lateralis243.92 ± 121.63280.54 ± 166.16302.61 ± 191.80

Abbreviation: EMG = electromyography; MVIC = maximum voluntary isometric contraction. Graph form this study.

So, whilst the glutes and the outside muscle of the quadriceps (the "sweep", the vastus lateralis) worked well, the hamstrings were not.

And this is consistent with other studies: the squat is touted as insufficient for hamstring development.

So, if you're anything like me, you're thinking: "How the hell does this happen? How can we have all that weight on our back, squat down with it, and drive it up and it NOT use our hamstrings!?"

Well, research suggests that this is what our hamstrings are doing when we squat:

  • They provide a stabilising force at the knee
  • They direct force on the tibia (shin bone) in opposition to the anterior tibial force (see below) generated by the quadriceps.
Lower Leg Diagram
Muscles in the Anterior Compartment of the Leg

The long and short of it is that the hamstrings work to stabilise us during squats, and do not work to "lift" the weight.

It's kind of like how a kitchen hand isn't exactly a chef, they just assist the chef.

Another study compared hamstring activity during the:

  • Back squat
  • Leg curl
  • Stiff-leg deadlift

And back squats were found to engage the hamstrings at about half the rate of leg curls and stiff-legged deadlifts.

So yes: hamstrings are worked during squats, but insufficiently… 

Your hamstrings are worked the most during the first stage of the descent into a squat; when you first begin to bend your knees (120 degrees or less of knee flexion). After that, there’s not much to get excited about.

It's key we remember that hamstring development is important to ensure muscle balance between the quads and hamstrings. This balance can help prevent injury!

So obviously, if maximum hamstring growth is the goal, we need to do more than just squats. The aforementioned leg curls are great, as are the stiff-legged deadlifts.

But don’t forget the Nordic curls, which we should all incorporate!

Optimal hamstring growth

This recent study investigated how our hamstring fibres are recruited and the force they generate during three different exercises.

The three exercises performed by the ten male participants in their twenties were:

  • The Nordic hamstring curl
  • Single-leg Roman chair
  • Single-leg deadlift

Here are these exercises in action Experimental set-up for the single-leg deadlift (A), Nordic hamstring curl (B), and the single-leg Roman chair hold (C)

Ok, so what did they find?

Amongst many things, the Nordic curl was very effective in comparison to the other exercises.

How to do Nordic curls

Nordic curls on the lat pulldown.

How to do Nordic curls on the lat pulldown

Step 1: Start at the top with your feet firmly locked in under the knee rest on the lat pulldown as seen above. Make sure the knee rest (that's where his heels are, not to be confused with the pad his knees are on) is as low as possible, as even a setting higher makes it possible for your feet to slip out. Start slightly angled forward as you can see from the starting position image above.

Step 2: Come down slowly (3-4 seconds) from an upright position towards the ground, always with your hands out for safety. You can see our subject has an esky there to push off. Always start with that (but a bench, instead) and as you get more confident, use the floor to push off.

Step 3: Push off the bench/floor with your hands and be sure it's not a big torso thrust, but your hamstrings that move and "lift" you back to your starting position. The difficulty of the exercise will be in how much you push yourself off the floor or bench, making it either easier or harder to return to the starting position.

It's really important to remember that on the way down to the floor, you come down slowly, over about 3-4 seconds, focusing on your hamstrings doing the bulk of the work. Again, ensure the knee pads on the lat pulldown are right down low and are firmly in place.

And we must stress again the key part to making the exercise harder: the less you push off the floor, the harder the rep back up is.

Eventually, you'll be able to perform around 8-10 reps. And as you get more experienced, you'll be able to push less off the floor, and even take longer on the eccentric movement for added work for your hamstrings.

And you can apply the important muscle growth principle of progressive overload by utilising a weight vest.

The bottom line on squats activating your hamstrings

Squats will not work your hamstrings effectively. This is because they work to stabilise your quads and legs during the squat movement and aren’t directly involved in the lifting.

Hamstrings are engaged at 120 degrees of knee flexion (the first 10-20% of your descent into the squat) and after that are not used much at all. Squats activate your hamstrings at roughly 50% of the rate of stiff-legged deadlifts and hamstring curls.

For optimal hamstring development, perform single-leg roman chairs, single-leg deadlifts and nordic curls.

References:

  1. Contreras B, Vigotsky AD, Schoenfeld BJ, Beardsley C, Cronin J. A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyography Amplitude in the Parallel, Full, and Front Squat Variations in Resistance-Trained Females. J Appl Biomech. 2016 Feb;32(1):16-22. doi: 10.1123/jab.2015-0113. Epub 2015 Aug 6. PMID: 26252837.
  2. Ebben WP, Leigh DH, Jensen RL. The role of the back squat as a hamstring training stimulus. Strength Condit J. 2000;22(5):15. doi:10.1519/00126548-200010000-00004
  3. Isear, J.A., J.C. Erickson, and T.W. Worrell. EMG analysis of lower extremity muscle recruitment patterns during an unloaded squat. Med. Sci. Sports Exerc. 29:532–539. 1997.
  4. Wright, G.A., T.H. Delong, and G. Gehlsen. Electromyographic activity of the hamstrings during performance of the leg curl, stiff leg dead lift and back squat movements. J. Strength Cond. Res. 13:168–174. 1999.
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