Good morning

Movement

What the lifter does

In a 2015 study’s description, the barbell rests on the upper trapezius, the large muscle across the upper back and neck¹. It sits slightly higher than in a back squat, and the feet are about shoulder width apart¹. The lifter leans forward by bending at the hips until the trunk is roughly parallel with the floor¹. Extending the hips then brings the lifter back up¹.

A 2013 biomechanics paper describes it as used mainly by weightlifters, to strengthen the gluteus, hamstrings and erector spinae⁵. The authors of the 2015 study wrote that many strength and conditioning coaches use it for the hamstrings and spinal erectors¹. They added that little research existed on its muscle activity and joint motion¹.

How much the knees bend

Mean knee bend in the studies here ranged from about 5 degrees to about 40 degrees^3,5:

Who was studied, and how	Mean knee bend
13 subjects told not to bend their knees, lifting an extra 25% of body weight	5.3 degrees5
15 trained men given no instruction on depth, lighter load	17.1 degrees1
The same 15 men, heavier load	24.8 degrees1
Eight women, range left to their own capabilities	About 40 degrees3

The lighter load was 50% of one-repetition maximum, the heaviest load a person can lift once, and the heavier was 90%¹.

How far the hips and back bend

In the 15 trained men, peak hip flexion (bending) was about 75 degrees¹. Flexion of the lumbar spine, the lower back, was about 25 to 27.5 degrees¹. The exercise is assumed to be pure hip extension with a neutral spine, one in its natural resting position¹. In 15 trained men, the spine did not stay neutral during the good morning; it moved through flexion and extension¹.

In 15 trained men, the spine did not stay neutral during the good morning; it moved through flexion and extension.

The 13 subjects lifted an extra 25% of body weight⁵. Their peak hip flexion was 25% smaller in the straight-knee good morning than in the deadlift⁵.

What it loads

What EMG showed in the hamstrings and back

The hamstrings extend the hip and flex the knee^6,7. The erector spinae is the main muscle that extends the vertebral column, the spine⁶. One study measured both in the 15 trained men with electromyography (EMG), which picks up a muscle’s electrical signals¹. It reported hamstring EMG as a share of maximal voluntary isometric contraction (MVIC), a muscle’s hardest effort while the joint stays still¹. Erector spinae EMG was relative to a maximal prone (face-down) back-extension effort¹:

Muscle measured	Mean EMG at 50% of one-repetition maximum	Mean EMG at 90%
Medial (inner) hamstrings	26.2% of MVIC1	39.9% of MVIC1
Lateral (outer) hamstrings	19.5% of MVIC1	30.4% of MVIC1
Lumbar (lower back) erector spinae	50.8% of the maximal effort1	70.9% of the maximal effort1
Thoracic (chest level) erector spinae	46.4% of the maximal effort1	66.6% of the maximal effort1

The lumbar erector spinae showed the highest mean EMG, relative to maximal effort, of the muscles measured¹. The authors note this could reflect the maximal test position, or how fully each man contracted his back muscles in it¹.

Other reports give more context^1,8,9:

• With no load. In an earlier study the 2015 authors report, erector spinae activity was about 17% of MVIC (thoracic) and 12.5% (lumbar)¹.
• 12 weight-trained men at 85% of one-repetition maximum. Of four exercises that included the good morning, hamstring activity was highest in the Romanian deadlift and the glute-ham raise⁸. The Romanian deadlift is a deadlift variant with slightly bent knees.
• A systematic review of 29 EMG studies. A systematic review searches for the research on a question in a set, checkable way. Good mornings gave a mean activation of 22.79% of MVIC in the long head of the biceps femoris, a hamstring muscle⁹. The deadlift category gave 42.17% and Nordic hamstring exercises 76.5%⁹. The review did not take exercise load into account⁹.

A review of exercises meant to condition the lumbar extensors counted good mornings among free-weight exercises¹⁰. It found evidence that the reviewed exercises may significantly activate the lumbar erector spinae and the multifidus, a deep muscle running along the spine¹⁰.

How long the hamstrings get

In the 15 trained men, estimated peak length of the biceps femoris long head was 1.111 to 1.124 times resting length¹. That is greater than a published value for sprinting, 1.098¹. The authors note that their estimates were not specific to each subject¹.

What models estimate with straight and bent knees

One modelling study had 13 participants do straight-knee good mornings with an extra 25% of body weight². Another had eight women lift 25% of body weight with about 40 degrees of knee bend³. The two reported:

• Hamstrings. With straight knees, the hamstrings were loaded isometrically, working without joint movement, in good mornings but dynamically in deadlifts².
• Gluteus maximus. The gluteus maximus works with the hamstrings to extend the hip¹¹. With straight knees, its computed force was significantly lower than in the deadlift and the split squat². With bent knees in the eight women, it was much higher than in that earlier study³. The authors attribute the difference to the greater knee bend³.
• Quadriceps. With straight knees, the model computed almost no force in the quadriceps, the four muscles on the front of the thigh². With bent knees in the eight women, the rectus femoris, one of the four, was active throughout³.

What models estimate for the lower spine

In the 13 subjects, the calculated moment (turning effect) at L4/L5 was the same in the good morning as in the deadlift⁵. Both lifts used an extra 25% of body weight⁵. L4/L5 is the joint between the fourth and fifth bones of the lower back, the lumbar vertebrae.

A 2002 conference paper modelled low back forces in four male nationally ranked weightlifters, each using a typical training load⁴. Its forces are model estimates, averaged over the four lifters⁴. They are for the erector spinae and for L5/S1, the joint at the base of the spine⁴:

Measure	Good morning	Romanian deadlift
Mean mass on the bar	67.5 kg1,4	125.0 kg1,4
Peak erector spinae force	5929.6 N1,4	5696.2 N1,4
Peak erector spinae force divided by bar weight	9.434	4.614
Peak L5/S1 compressive force divided by bar weight	10.664	5.454

The model put mean peak L5/S1 compressive (squeezing) force in the good morning at 6712.7 N, or newtons, a unit of force⁴. Peak shear force, which pushes two surfaces to slide across each other, was 1227.8 N⁴. Divided by bar weight, erector spinae force and L5/S1 compressive force were significantly higher in the good morning than in the Romanian deadlift⁴. The study could not analyse the lowering phase⁴.

The paper concluded that coaches should consider the possibility of low back injury with the good morning and the bent-over row⁴. It estimated forces and did not measure injuries⁴. One 2020 narrative review, a summary written without a set search method, as summarised by a later review, says good mornings should generally be avoided¹². That summary reports no injury counts for the good morning¹².

The joints where a disc sits between two vertebrae (spine bones) carry most of the weight the spine bears¹³. The intervertebral disc page covers that pad of cartilage.

How the body adapts

The authors of the 2015 EMG study wrote that the exercise may be an effective way to strengthen the erector spinae¹. They added that training studies are needed to show this¹.

A review of lumbar extensor training studies grouped good mornings with deadlifts and squats as free-weight exercises¹⁰. It found evidence that these may be less effective at producing lasting adaptations in the lumbar extensors than machines that restrain the pelvis¹⁰. It gives a possible reason: other muscles, such as those that extend the hip, take part¹⁰.

One training study involved 12 female college soccer players^5,14. They did six weeks of strength training with two added hamstring exercises^5,14. A later paper reports that the exercises used included good mornings and straight-leg deadlifts^5,14. The ratio of eccentric hamstring strength to concentric quadriceps strength rose from 0.96 to 1.08, with no significant change in the conventional ratio^5,14. Eccentric work is done while a muscle lengthens and concentric work while it shortens.

Two suggestions by study authors rest on measurements of the movement^1,5:

• The 2015 authors postulated that the exercise might reduce the risk of hamstring strains¹. Their study did not measure injuries¹.
• The 2013 authors measured joint moments and angles in 13 subjects lifting light barbell loads⁵. From these, they suggested ranking the good morning ahead of the deadlift and squat for shifting the hamstring-to-quadriceps balance towards the hamstrings⁵. Their study measured no strength or injury outcomes⁵.

Progressive overload

The progressive overload page covers the principle. For the good morning, the 15 trained men lifted 50, 60, 70, 80 and 90% of an estimated one-repetition maximum¹. As the load rose:

• Muscle activity tended to increase in the hamstrings and spinal erectors, measured as integrated EMG, the signal added up over time¹.
• Mean hamstring EMG levelled off between 80% and 90%¹. Integrated EMG of the lateral hamstrings was still significantly greater at 90% than at 80%¹.
• Knee bend at the bottom increased, from a mean of 17.1 to 24.8 degrees¹.
• Estimated hamstring length at the bottom decreased¹.
• Hip and lumbar flexion showed no remarkable change¹.

The maximum was estimated from a set of as many repetitions as possible with a moderately heavy load¹. The authors note that this method has not been validated for the good morning¹.

In another study, of 21 male collegiate athletes, six-repetition-maximum squat load was a significant predictor of good morning load¹⁵. In 13 female collegiate athletes analysed separately, it was not a significant predictor¹⁵.

Connections

The sources here link the good morning to these muscles^1,5:

• The hamstrings, which the 2015 authors describe as lengthening under load as the hips flex and shortening as they extend¹.
• The gluteus maximus, whose modelled force was much higher in a bent-knee study of eight women than in a straight-knee study³.
• The erector spinae, whose lumbar part showed the highest mean EMG, relative to maximal effort, in 15 trained men¹.
• The multifidus, which a review found its exercises may significantly activate¹⁰.
• The quadriceps, almost unloaded in a straight-knee model².

In 15 trained men, the movement flexed the hip, the knee and the lumbar spine¹. In 13 subjects lifting an extra 25% of body weight with straight knees, the external moment at the knee was an extension moment⁵. Related exercise pages: the deadlift and split squat, which a modelling study compared with the good morning².

Sources

1. Vigotsky AD, Harper EN, Ryan DR, Contreras B (2015). Effects of load on good morning kinematics and EMG activity.. PeerJ. doi:10.7717/peerj.708 PMID 25653899
2. Schellenberg F, Taylor WR, Lorenzetti S (2017). Towards evidence based strength training: a comparison of muscle forces during deadlifts, goodmornings and split squats.. BMC sports science, medicine & rehabilitation. doi:10.1186/s13102-017-0077-x PMID 28725437
3. Jaeggi JS, Achermann B, Lorenzetti SR (2024). Female Lower Body Muscle Forces: A Musculoskeletal Modeling Comparison of Back Squats, Split Squats and Good Mornings.. Journal of functional morphology and kinesiology. doi:10.3390/jfmk9020068 PMID 38651426
4. Burnett A, Beard A, Netto K (2002). Back stress and assistance exercises in weightlifting. ISBS - Conference Proceedings Archive (20th International Symposium on Biomechanics in Sports, Cáceres, Spain), pp. 421-424. Link
5. Schellenberg F, Lindorfer J, List R, Taylor WR, Lorenzetti S (2013). Kinetic and kinematic differences between deadlifts and goodmornings.. BMC sports science, medicine & rehabilitation. doi:10.1186/2052-1847-5-27 PMID 24314057
6. Betts JG, Young KA, Wise JA, Johnson E, Poe B, Kruse DH, Korol O, Johnson JE, Womble M, DeSaix P (2022). Anatomy and Physiology 2e. OpenStax. Link
7. Obey MR, Broski SM, Spinner RJ, Collins MS, Krych AJ (2016). Anatomy of the Adductor Magnus Origin. Orthopaedic Journal of Sports Medicine. doi:10.1177/2325967115625055 PMID 26798764
8. McAllister MJ, Hammond KG, Schilling BK, Ferreria LC, Reed JP, Weiss LW (2014). Muscle activation during various hamstring exercises.. Journal of strength and conditioning research. doi:10.1519/JSC.0000000000000302 PMID 24149748
9. Llurda-Almuzara L, Labata-Lezaun N, López-de-Celis C, Aiguadé-Aiguadé R, Romaní-Sánchez S, Rodríguez-Sanz J, Fernández-de-Las-Peñas C, Pérez-Bellmunt A (2021). Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review.. International journal of environmental research and public health. doi:10.3390/ijerph18168733 PMID 34444481
10. Steele J, Bruce-Low S, Smith D (2013). A review of the specificity of exercises designed for conditioning the lumbar extensors.. British journal of sports medicine. doi:10.1136/bjsports-2013-092197 PMID 24092889
11. Lee DK, Oh JS (2018). Relationship between hamstring length and gluteus maximus strength with and without normalization.. Journal of Physical Therapy Science. doi:10.1589/jpts.30.116 PMID 29410579
12. Bonilla DA, Cardozo LA, Vélez-Gutiérrez JM, Arévalo-Rodríguez A, Vargas-Molina S, Stout JR, Kreider RB, Petro JL (2022). Exercise Selection and Common Injuries in Fitness Centers: A Systematic Integrative Review and Practical Recommendations.. International journal of environmental research and public health. doi:10.3390/ijerph191912710 PMID 36232010
13. Waxenbaum JA, Reddy V, Futterman B (2026). Anatomy, Back, Intervertebral Discs. StatPearls. PMID 29262063
14. Holcomb WR, Rubley MD, Lee HJ, Guadagnoli MA (2007). Effect of hamstring-emphasized resistance training on hamstring:quadriceps strength ratios.. Journal of strength and conditioning research. doi:10.1519/R-18795.1 PMID 17313266
15. Ebben WP, Long NJ, Pawlowski ZD, Chmielewski LM, Clewien RW, Jensen RL (2010). Using squat repetition maximum testing to determine hamstring resistance training exercise loads.. Journal of strength and conditioning research. doi:10.1519/JSC.0b013e3181cbabd5 PMID 20072071

Every source the library cites

Changes

• October 9, 2026 First published.