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Decline squat

Also called single-leg decline squat, decline board squat

A squat, most often on one leg, done on a sloped board. What studies measured it loading, from the patellar tendon to the thigh and calf muscles, and what training and trials in people with patellar tendon pain found.

Region
Knee
Muscles
quadriceps, gastrocnemius, hamstrings, tibialis anterior
Updated
October 23, 2026
Reviewed
October 23, 2026 · how entries are checked

Movement

The squat on a slope

One study had five people squat on boards set at angles from 0 to 30 degrees4. The steeper the board, the larger the maximum knee and ankle angles4.

In one laboratory comparison, the knee and ankle moved through larger angles on a decline board than on flat ground5. In 13 people, the ankle and hip angles at the end of the squat were significantly smaller on a 25-degree slope than on flat ground1.

One study tested one-leg squats in 33 people awaiting hip arthroscopy (keyhole surgery inside a joint) and 33 matched healthy people12. Across all 66 people, the 25-degree board cut inward knee movement by about 1 cm in both legs12.

The versions studies have used

  • Eccentric squats on one leg, where the muscles work while lengthening as the body lowers1,4.
  • A held squat at 90 degrees of knee bend on one leg1.
  • Held squats at 45, 60 and 90 degrees of knee bend, on a 25-degree wedge6.
  • Added weight: a 10 kg backpack, a free weight, or 70% to 90% of the one-repetition maximum, the heaviest weight a person can lift once4,5,13.
  • An eccentric-overload machine called the Bromsman5.

The Spanish squat

In the version one group of authors studied, a rigid strap is fixed just below the line of the knee joint10.

What it loads

The patellar tendon

The patellar tendon runs from the patella (kneecap) to the front of the tibia (shinbone), just below the knee2. Several studies compared its load on a slope and on flat ground1,4,5,13:

  • Strain. In 13 people holding a one-leg squat at 90 degrees, tendon strain was significantly greater on the 25-degree slope1.
  • Board angle. In five people, boards sloped more than 15 degrees gave a 40% rise in peak tendon force4.
  • Free weight. In one laboratory comparison, peak and mean tendon force were 25% to 30% greater on the decline board5. That difference was not seen in the Bromsman machine5.
  • Heavy barbell. In 12 healthy people doing heavy one-leg back squats, modelled peak tendon force was significantly higher on the decline board13.

Modelled means estimated with a model rather than measured directly. In those same 12 people, raising the barbell from 70% to 90% of the one-repetition maximum did not significantly raise peak tendon force13. That held on the decline board and on level ground13.

One study of 20 healthy adults scored 35 exercises on a patellar tendon loading index3. The index combined peak load, loading rate and total load over time into one score3. The single-leg decline squat scored highest of the 353. It also scored above two other one-leg squats3:

Patellar tendon loading indexSingle-leg decline squat0.747 Single-leg full squat0.580 Single-leg squat to 60 degrees0.411
Patellar tendon loading index. Bars start at zero; the table below gives each value with its source.
Squat, in 20 healthy adultsPatellar tendon loading index
Single-leg decline squat0.7473
Single-leg full squat0.5803
Single-leg squat to 60 degrees0.4113

In the five-person study, patellofemoral force, the force pressing the kneecap against the thigh bone, rose with steeper boards too4. Past 60 degrees of knee bend, it rose more steeply than the tendon force4.

The quadriceps and the knee

The quadriceps is the group of four muscles on the front of the thigh that straighten the knee2. It acts through the kneecap and patellar tendon2. The studies here reported these findings at the knee1,4:

  • In five people, the knee moment was 40% higher on boards of 15 degrees and above4. On a 25-degree board, a 10 kg backpack raised it by a further 23%4.
  • In 10 people without pain or injury, the knee moment and rectus femoris activity rose as the board got steeper14. The rectus femoris is the quadriceps muscle at the front of the thigh that also bends the hip.
  • In 13 people, activity in the knee extensors, the muscles that straighten the knee, was significantly greater on the slope than on flat ground1.
  • In 26 adults, rectus femoris activity was significantly higher on a 25-degree wedge at 45, 60 and 90 degrees of knee bend6.
  • In one laboratory comparison with a free weight, vastus medialis activity was 6% greater on the decline board5. The vastus medialis is the quadriceps muscle on the inner side of the thigh.

Where the sources differ: the angle of the board

The five-person study found hip and ankle moments fell as the knee moment rose on boards of 15 degrees and above4. The authors of the 10-person study concluded that boards past 16 degrees may not lessen passive tension in the calf, as had been suggested14. They also concluded such boards may give no mechanical advantage for the knee14.

The calf, shin and hamstrings

Four studies measured calf muscle activity, and their findings do not agree1,5,6,14. Three of them measured the gastrocnemius, the large two-headed calf muscle, by name5,6,14:

StudyCalf muscle activity on the slope compared with flat ground
13 people, one-leg eccentric squatsCalf activity did not differ1
One laboratory comparison, free weightActivity 13% greater5
26 adults, held squatsOuter gastrocnemius activity significantly lower at 90 degrees of knee bend6
10 people without pain or injuryAnkle moment fell as the board got steeper, but activity rose between 16 and 24 degrees14

In the same 26 adults, tibialis anterior activity was significantly lower on the wedge6. The tibialis anterior is the muscle at the front of the shin that pulls the foot up.

The hamstrings are the three long muscles at the back of the thigh. In the 13-person study, their activity did not differ between the slope and flat ground1. In the 26 adults, activity in four muscles rose with deeper knee bend, on the wedge and on flat floor6. These were biceps femoris (a hamstring muscle), rectus femoris, outer gastrocnemius and tibialis anterior6.

The quadriceps tendon

The quadriceps tendon is the shared tendon of the four quadriceps muscles2. The decline squat studies here measured patellar tendon load, not quadriceps tendon load1,4,5,13. In six cadaver knees, from bodies donated for study, the patellar tendon carried more force than the quadriceps tendon at 30 degrees of knee bend15. At 90 and 120 degrees, the quadriceps tendon carried more15.

What the Spanish squat loads

The Spanish squat evidence here is thin. The three studies tested 4, 20 and 22 people, and each measured load or muscle activity, not change with training3,10,11:

  • Tendon strain, 4 healthy people. Patellar tendon strain was smallest in the Spanish squat10. It was below a knee extension at 60% of maximal isometric effort, a muscle’s hardest effort while the joint stays still10. Adding electrical stimulation gave about double the strain or more10.
  • Loading index, 20 healthy adults. The Spanish squat fell in the middle of three tendon loading tiers3.
  • Muscle activity, 22 active men. Rectus femoris activity was higher than in a free-standing squat11.

How the body adapts

Two reports on the same design each randomly divided 36 volunteers into three groups, including 13 controls who did not train16,17. The other two groups trained the eccentric single-leg decline squat for six weeks, lowering over 6 or 3 seconds16.

Tendon and muscle size

  • Six-second lowering. In the 11 people in this group, patellar tendon thickness rose by about 21.8%16.
  • Three-second lowering. In these 12 people, thickness of the vastus lateralis, the quadriceps muscle on the outer thigh, rose by about 15.7%16.

Strength, and what happened after stopping

In the two training groups, the decline squat one-repetition maximum rose by about 92% to 95%17. Peak torque in a held knee extension rose by about 12%17. Peak torque is the greatest turning force a muscle produces about a joint. There was no difference between the 3-second and 6-second groups17.

After a further six weeks without training, strength in the two training groups fell in every test17. The decline squat one-repetition maximum dropped by 28% to 37%17.

Trials in people with patellar tendinopathy

Several trials in people with patellar tendinopathy reported pain and a knee-function questionnaire score called VISA18,19,20. Their results are mixed8,9,21.

Two studies compared the board with squats on flat ground or a step18,21:

  • Pilot, 17 people with long-standing tendon pain. The groups were not randomly assigned21. Over 12 weeks, pain during activity fell from 74.2 to 28.5 out of 100 in the 25-degree board group21. In the flat-foot group it did not change significantly21.
  • 17 elite volleyball players, randomised. Both the 25-degree board group, who exercised into tendon pain, and a 10 cm step group, who exercised without it, improved18. A 20-point VISA gain at 12 months was more likely in the board group18. The two groups’ pain scores did not differ at 12 months18.

Lowering against lifting: one trial studied athletes with jumper’s knee, a common name for tendon pain at the front of the knee19. They were randomly assigned to eccentric or concentric squats on a decline board for 12 weeks19. In the eccentric group, pain fell from 73 to 23 and VISA rose from 41 to 8319. The concentric group showed no significant change19. The study was stopped at its halfway check because of the concentric group’s poor results19.

Two trials compared other equipment and board angles20,22:

  • 20 athletes. One-leg decline board squats and two-legged training in the Bromsman machine both improved VISA over 12 weeks20. Pain and function did not differ significantly between the groups20.
  • 70 people, 35 per group. Both the 25-degree and the 17-degree board groups improved on every clinical measure at six weeks22. There was no significant difference between the two angles22.

Two trials compared board squats with other exercise, an injection and surgery7,23:

  • 39 men, randomised. The squat, heavy slow resistance (slow, heavy strength exercise) and steroid injection groups all improved in VISA and pain at 12 weeks23. At half a year the gains held in both exercise groups but not in the injection group23. Swelling and vascularisation (blood vessels in the tendon) fell in injection and heavy slow resistance groups, but the summary does not report the squat group23.
  • 35 people, 40 knees, grade IIIB patellar tendinopathy, randomised. VISA scores over 12 months did not differ between open tenotomy, surgery that cuts a tendon, and 12 weeks of 25-degree board squats7. Both groups improved7. In the squat group, 5 of 20 knees did not respond and had surgery after three to six months7. Of the other 15, seven were free of symptoms at 12 months and eight had improved but still had symptoms7.

During the playing season: 29 elite volleyball players kept training and competing, and were randomly assigned to 12 weeks of board squats or usual training8. VISA scores did not change in either group8. The board group did 8.2 sessions a week on average, 59% of the volume the study set8.

Two reviews and a pain study

A 2007 review of 7 trials of eccentric training in patellar tendinopathy, with 162 people in all, found positive results of variable quality24. The programmes differed in several ways, including whether squats were done on a decline board or level ground24. A 2020 systematic review with meta-analyses pooled randomised trials in patellar tendinopathy9. Adding another approach without injections, drugs or surgery to decline squats showed no overall short-term effect on pain or function9. The certainty of that evidence was low to very low9.

In 57 non-elite volleyball players aged 13 to 17, 26.3% felt pain during a single-leg decline squat25. Pain at the patellar tendon itself was recorded in 12.3% of right legs25. Players with that tendon pain had a thicker mid-tendon, more often with new blood vessels, than players with other knee pain or none25.

Progressive overload

A 2026 position stand describes progressive overload as the need to raise the stimulus on the muscle through a training programme26.

In healthy volunteers

In the six-week trial of 36 active volunteers, each session was 3 sets of 8 repetitions at 80% of the one-repetition maximum16. Sets were 2 minutes apart, three times a week, on a multipower machine16. Every 2 weeks, the training groups redid a 5-repetition-maximum test to update their loads16.

A second trial, in 50 people, compared 6-second with 3-second lowering27. The patellar tendon thickened in both groups, notably at its upper end with 3 seconds and its lower end with 627. The authors concluded these changes were lost after six weeks without training, while tendon stiffness rose27.

In people with patellar tendinopathy

Three trials set 3 sets of 15 repetitions twice a day for 12 weeks8,19,21. The 2007 review found programmes progressed with speed and then load, or with load alone24. In the 17 elite volleyball players, the board group progressed with load and the step group with speed, then load18.

In a trial of 76 patients, the board group were advised to add weight in a backpack if they felt little or no pain28. At 24 weeks, VISA-P scores rose more with a separate progressive tendon-loading programme than with the board squats: 28 against 18 points28. In 40 volleyball, basketball and handball athletes, 30 analysed, a 12-week progressive-loading programme of decline squats improved quadriceps strength and pain29. A control group that kept to usual sport did not29.

Connections

The tendons at the front of the knee

  • The patellar tendon, which showed greater strain and force on a slope in the studies here1,13.
  • The quadriceps tendon, which carried more force than the patellar tendon in deep knee bend in six cadaver knees15.

The muscles it works

  • The quadriceps, whose activity was greater on a slope, or rose on a steeper board, in three studies1,6,14.
  • The hamstrings, whose activity did not differ from flat ground in 13 people1.
  • The calf muscles, where four studies disagree1,5,6,14.
  • The tibialis anterior, less active on a 25-degree wedge in 26 adults6.

The study of 20 healthy adults also scored two-leg squats, which the back squat page covers3. The wall sit was compared with the Spanish squat in 22 active men11.

Decline squat loads

Decline squat works the muscle of

Decline squat is progressed by

Sources

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  2. 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
  3. Scattone Silva R, Song KE, Hullfish TJ, Sprague A, Silbernagel KG, Baxter JR (2024). Patellar Tendon Load Progression during Rehabilitation Exercises: Implications for the Treatment of Patellar Tendon Injuries.. Medicine & Science in Sports & Exercise. doi:10.1249/MSS.0000000000003323 PMID 37847102
  4. Zwerver J, Bredeweg SW, Hof AL (2007). Biomechanical analysis of the single-leg decline squat.. British journal of sports medicine. doi:10.1136/bjsm.2006.032482 PMID 17224441
  5. Frohm A, Halvorsen K, Thorstensson A (2007). Patellar tendon load in different types of eccentric squats.. Clinical biomechanics (Bristol, Avon). doi:10.1016/j.clinbiomech.2006.12.006 PMID 17499407
  6. Lee D, Lee S, Park J (2015). Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs.. Journal of physical therapy science. doi:10.1589/jpts.27.2617 PMID 26357447
  7. Bahr R, Fossan B, Løken S, Engebretsen L (2006). Surgical treatment compared with eccentric training for patellar tendinopathy (Jumperʼs Knee). The Journal of bone and joint surgery. American volume. doi:10.2106/jbjs.e.01181 PMID 16882889
  8. Visnes H, Hoksrud A, Cook J, Bahr R (2005). No effect of eccentric training on jumper's knee in volleyball players during the competitive season. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine. doi:10.1097/01.jsm.0000168073.82121.20 PMID 16003036
  9. Mendonça LM, Leite HR, Zwerver J, Henschke N, Branco G, Oliveira VC (2020). How strong is the evidence that conservative treatment reduces pain and improves function in individuals with patellar tendinopathy? A systematic review of randomised controlled trials including GRADE recommendations.. British journal of sports medicine. doi:10.1136/bjsports-2018-099747 PMID 31171514
  10. Basas C, Ito N, Grävare Silbernagel K, Reyes-Gil F, Basas Á (2023). The Basas Spanish Squat: Superimposition of Electrical Stimulation to Optimize Patellar Tendon Strain: A Case Series.. International journal of sports physical therapy. doi:10.26603/001c.89267 PMID 38050553
  11. Lee JH, Kim S, Heo J, Park DH, Chang E (2022). Differences in the muscle activities of the quadriceps femoris and hamstrings while performing various squat exercises.. BMC Sports Science, Medicine and Rehabilitation. doi:10.1186/s13102-022-00404-6 PMID 35063016
  12. Freke MD, Crossley K, Russell T, Sims KJ, Semciw A (2020). Changes in Knee and Trunk Alignment in People With Hip Pain and Healthy Controls When Using a Decline Board During Single-Leg Squat.. Journal of sport rehabilitation. doi:10.1123/jsr.2019-0097 PMID 31661674
  13. Hagen M, Chebly J, Dhaen B, Fassian N, Salvalaggio M, Catelli DS, Verschueren S, Vanrenterghem J (2024). Peak patellar tendon force progressions during heavy load single-leg squats on level ground and decline board.. Clinical Biomechanics. doi:10.1016/j.clinbiomech.2024.106179 PMID 38219457
  14. Richards J, Thewlis D, Selfe J, Cunningham A, Hayes C (2008). A biomechanical investigation of a single-limb squat: implications for lower extremity rehabilitation exercise.. Journal of athletic training. doi:10.4085/1062-6050-43.5.477 PMID 18833310
  15. Huberti HH, Hayes WC, Stone JL, Shybut GT (1984). Force ratios in the quadriceps tendon and ligamentum patellae.. Journal of Orthopaedic Research. doi:10.1002/jor.1100020108 PMID 6491798
  16. Abián P, Martínez F, Jiménez F, Abián-Vicén J (2020). Effects of Eccentric Single-Leg Decline Squat Exercise on the Morphological and Structural Properties of the Vastus Lateralis and Patellar Tendon.. International journal of environmental research and public health. doi:10.3390/ijerph17249410 PMID 33333987
  17. Abián-Vicén J, Martínez F, Jiménez F, Abián P (2022). Effects of Eccentric Single-Leg Decline Squat Training Performed With Different Execution Times on Maximal Strength and Muscle Contraction Properties of the Knee Extensor Muscles.. Journal of strength and conditioning research. doi:10.1519/jsc.0000000000004063 PMID 34085999
  18. Young MA, Cook JL, Purdam CR, Kiss ZS, Alfredson H (2005). Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players.. British journal of sports medicine. doi:10.1136/bjsm.2003.010587 PMID 15665207
  19. Jonsson P, Alfredson H (2005). Superior results with eccentric compared to concentric quadriceps training in patients with jumper's knee: a prospective randomised study.. British journal of sports medicine. doi:10.1136/bjsm.2005.018630 PMID 16244196
  20. Frohm A, Saartok T, Halvorsen K, Renström P (2007). Eccentric treatment for patellar tendinopathy: a prospective randomised short-term pilot study of two rehabilitation protocols.. British journal of sports medicine. doi:10.1136/bjsm.2006.032599 PMID 17289855
  21. Purdam CR, Jonsson P, Alfredson H, Lorentzon R, Cook JL, Khan KM (2004). A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy.. British journal of sports medicine. doi:10.1136/bjsm.2003.000053 PMID 15273169
  22. Knež V, Hudetz D (2023). Eccentric Exercises on the Board with 17-Degree Decline Are Equally Effective as Eccentric Exercises on the Standard 25-Degree Decline Board in the Treatment of Patellar Tendinopathy.. Medicina (Kaunas, Lithuania). doi:10.3390/medicina59111916 PMID 38003964
  23. Kongsgaard M, Kovanen V, Aagaard P, Doessing S, Hansen P, Laursen AH, Kaldau NC, Kjaer M, Magnusson SP (2009). Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy.. Scandinavian journal of medicine & science in sports. doi:10.1111/j.1600-0838.2009.00949.x PMID 19793213
  24. Visnes H, Bahr R (2007). The evolution of eccentric training as treatment for patellar tendinopathy (jumper's knee): a critical review of exercise programmes.. British journal of sports medicine. doi:10.1136/bjsm.2006.032417 PMID 17261559
  25. Coombes BK, Mendis MD, Hides JA (2020). Evaluation of patellar tendinopathy using the single leg decline squat test: Is pain location important?. Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine. doi:10.1016/j.ptsp.2020.10.002 PMID 33059234
  26. Currier BS, D'Souza AC, Singh MAF, Lowisz CV, Rawson ES, Schoenfeld BJ, Smith-Ryan AE, et al (2026). American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews.. Medicine and science in sports and exercise. doi:10.1249/MSS.0000000000003897 PMID 41843416
  27. Martínez F, Abián P, Jiménez F, Abián-Vicén J (2022). The Effects of Eccentric Contraction Execution Time on the Properties of the Patellar Tendon.. International journal of environmental research and public health. doi:10.3390/ijerph19159296 PMID 35954651
  28. Breda SJ, Oei EHG, Zwerver J, Visser E, Waarsing E, Krestin GP, de Vos RJ (2021). Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial.. British journal of sports medicine. doi:10.1136/bjsports-2020-103403 PMID 33219115
  29. Fendri T, Beaune B, Rebai H, Chaari F, Harrabi MA, Rahmani A, Boyas S, Sahli S (2026). Progressive tendon-loading eccentric exercise therapy in athletes with patellar tendinopathy improves postural control, quadriceps strength, and pain: A randomized clinical trial.. Journal of ISAKOS. doi:10.1016/j.jisako.2026.101105 PMID 41905494

Every source the library cites

Changes

  • Added a Progressive overload section.
  • Tidy pass: minor review findings fixed, glosses aligned with the reviewed glossary.
  • First published.