Case study: Sam, yoga instructor
This is Sam. Sam booked his first appointment at the clinic 2 weeks ago. He was suffering with pain in his right lower back, mid back and a restriction when trying to achieve deep overhead positions in yoga.
Treatment: How I reduced his back pain
Suffering from an injury?
You can also follow Sam on instagram: @sbarrett94
Effects of two different injury prevention resistance exercise protocols on the hamstring torque-angle relationship – a randomized controlled trial, by Naclerio, Larumbe-Zabala, Monajati, and Goss- Sampson, in Research in Sports Medicine (2015)
Hamstring strains are a common injury in many popular team sports and they lead to the loss of many hours of training and competition, as well as a very high re-injury rate. Hamstring strains account for 12 – 16% of all injuries in athletes across a range of popular team sports, including rugby, soccer, American Football, and Australian Rules Football. The re-injury rate for hamstring strains ranges from 16 – 34%, depending upon the sport. Running activities account for most hamstring strains, with 57 – 68% of strains occurring during running. The traditional model for hamstring strain injury is that there are various factors that could cause an injury to occur, including: flexibility, strength, fatigue, core stability, muscle architecture, and damage resulting from previous injury. A modern, more sophisticated approach has suggested that while these factors could individually lead to an injury, it is more likely that they interact with each other in order to create multi-factorial scenarios that raise injury risk. Some researchers have suggested that there are at least two different types of hamstring strain injury: those caused by stretching activities and those caused by high-speed running movements. The hamstring strain injury caused by high-speed running is thought to occur most normally in the long head of biceps femoris, typically involves the proximal muscle-tendon junction, displays a greater reduction in strength following injury than those following stretching movements, and leads to a relatively long recovery time to reach pre-injury levels of performance (e.g. around 50 weeks). The biceps femoris (long head) is generally thought to be the most commonly-injured hamstring muscle, although some researchers have suggested that this perception might be incorrect because of inherent errors in common diagnostic approaches. Biomechanically, however, there are good reasons for assuming that the biceps femoris might be most at risk. Firstly, this muscle increases in length by more than the other hamstring muscles during sprinting. Secondly, the moment arm lengths of the biceps femoris in the sagittal plane increase in the late swing position compared to the anatomical position. Previous research has identified that hamstring strains occur most frequently either in the late swing or early stance phases of gait. Late swing involves the greatest strain in the muscle, while early stance involves the largest joint moments. There is good evidence to suggest that hamstring strain injuries can be reduced by eccentric hamstring training but not by flexibility training alone. This has encouraged many strength coaches to incorporate the Nordic hamstring curl into hamstring strain prevention programs. However, there is only limited evidence to suggest that hamstring weakness predicts strain injury risk.
OBJECTIVE: To compare the effects of two different 6-week lower body injury prevention programs on the knee flexion torque–angle relationship (by measuring maximal voluntary isometric contraction (MVIC) knee flexion torque at 35, 45, 60, 80, 90, and 100 degrees) before and after the intervention.
POPULATION: 32 recreationally-trained male soccer players, aged 22.2 ± 2.6 years, randomly allocated to 3 groups: hamstring eccentric (ECC), unstable squat (UNS), and control (CON).
INTERVENTION:The two training groups trained twice per week for 6 weeks using 3 individual hamstring eccentric (ECC) or unstable squat (UNS) exercises, respectively. ECC performed the coach- and band-assisted assisted Nordic hamstring curl, the eccentric single-leg stiff-legged deadlift, and the eccentric two-leg stiff-legged deadlift. UNS performed the single-leg squat, the single-leg squat on a BOSU ball, and forward lunges on a BOSU ball.
Knee flexion torque-angle relationship
At baseline, the researchers reported that all 3 groups displayed peak torque at between 45 and 80 degrees of knee flexion angle and there were no differences between groups.
Changes in knee flexion torque-angle relationship
The researchers reported that MVIC knee flexion torque increased at 35 and 45 degrees in ECC and at 60, 80 and 90 degrees in UNS.
What did the researchers conclude?
The researchers concluded that ECC increased knee flexion torques at the two most open knee flexion angles (35 and 45 degrees) where the hamstrings are lengthened while UNS improved at more closed knee angles (60, 80, and 90 degrees) where the hamstrings are less lengthened. This suggests that exercises that display peak torque at long muscle lengths tend to increase strength most at long muscle lengths while exercises that display peak torque at short muscle lengths tend to increase strength most at short muscle lengths.
The study was limited in that it is unclear whether the unstable surface was necessary for the UNS condition. It is possible that a simple single-leg squat program would have produced similar results without the need for the instability condition.
The Hip Pinch – how to fix
Ever been squatting and felt that annoying pinch at the front of your hip? Don’t worry you are not the only one! This is easily one of the most common complaints from CrossFitters/Weightlifters. The hip pinch that is being felt is known as Femoral Acetabular Impingement (FAI) and can occur due to a variety of restrictions when squatting. [Read more…]
The importance of correct squat biomechanics
Squats, squats and more squats. Squats are great but are you performing the correct squat biomechanics? You might think, “oh a squat is a squat”, however, to perform squats to your fullest potential and avoid injury the correct biomechanics need to be used.
Everyone squats differently and there isn’t a ‘one squat fits all’ otherwise that would be easy peasy. There are narrow squatters and wide squatters, which one are you? If you don’t know this it can easily be assessed and will allow you to perform a squat injury free and to your fullest potential. Once you have established this there is a set of guidelines we should follow to allow us to perform a squat without the risk of injury.
Correct squat biomechanics
Squats like any exercise you participate has its injury risks, therefore, it is important we perform the correct squat biomechanics (Chandler et al). Not only will performing the correct squat biomechanics keep you injury free it will also allow you to perform a GREAT squat, hit the musculature we want and avoid overloading of particular structures susceptible to injury.
Things we need to be aware of when squatting to keep away from common faults…
1) Make sure lumbar extension is not lost when squatting as this can increase the chances of back injury (not rounding at the bottom of the squat also known as butt winking).
2) Make sure your knees DON’T track inside of your feet (valgus knees).
3) Make sure you reach at least parallel in a squat (providing you have the mobility to do so).
4) Make sure full hip extension is performed at the top of the squat. Hip extension is one of the most important movements in a squat, with glute activation being 80-120% of muscle voluntary contraction (MVC) in the concentric phase of the exercise (rising up), compared to 20-30% MVC in the eccentric phase (lowering).
5) Heels need to be kept on the ground at all times.
6) Stability and mobility of the joint is very important when performing a squat. These need to be balanced to allow the joint to move through full available range of motion and for the surrounding muscles to stabilise this movement, to avoid any injury (Contereas 2013, Glassman 2002, Cressay 2014 and DeBell 2014).
Are you performing these movements when squatting?
Or are you turning these into common faults? Every time you perform a squat and perform one of this common faults incorrect squat biomechanics is increasing your risk of injury.
Already previously mentioned, everyone squats differently due to our anatomical make up. Our bony anatomy will dictate whether we are a narrow squatter or a wide squatter, the rest of our squat is determined by our stability and mobility (DeBell 2014). Due to this we need to ensure our stability and mobility when performing the squat is on top form to avoid any chances of injury. Just because you’re squatting with a narrow stance doesn’t mean you’re squatting wrong. You maybe squatting incorrectly if you’re not following some of the guidelines previously mentioned.
A common fault is the butt wink. Ever being told you are butt winking and not known what this is? This is basically when you lose your neutral lumbar spine. This is very common in squatters, increasing your chance of lower back injury due to compressive and shearing forces on the spine (Contreras 2013 and Chandler et al). This is where your pelvis posteriorly tilts causing your spine to be forced into lumbar flexion. This movement occurs when hip range is at the athlete’s limits, putting athletes at risk of disc herniation and damaging of spinal ligaments.
Another common fault is forgetting about your knees. Do you squat and feel your knees tracking inwards? This usually occurs in athletes to stabilise themselves to allow participants with weak gluts to perform a squat. This however, will be increasing the risks of injury such as chronic knee syndromes etc. patellofemoral pain syndrome and knee osteoarthritis (Contreras 2013).
Why might your squat mechanics be dysfunctional?
When we are thinking about squatting you automatically think your hip. There are many considerations we need to think about when it comes to squatting such as the spine, knees and ankles (DeBell 2014).
Hip strength is incredibly important for the squat. Knee pain when squatting? This is likely due to poor hip strength of the gluteal muscles such as gluteus medius which can be overpowered by the hip adductors causing valgus knees to stabilise the femur in squatting (where you knees track inwards) (Contereas 2013).
Weak hips can also lead to poor muscle engagement of the surrounding muscles of the hips such as the hamstrings and gluts, which could lead to squatting with the overuse of the quadriceps (Glassman 2002). It is important to have coordination between the glutes, hamstrings and the quadriceps to allow a squat to be performed pain free (Conteras 2013). Weakness in one can inhibit the powerful hip extension that is needed to allow you to fully perform a squat (Glassman 2002).
Impaired function of the hamstrings and vastus medialis function such as decreased strength will cause valgus knees due to decreased stabilisation of knee increasing overloading of the knee joint. Decreased flexibility of the hamstrings will force you into lumbar flexion to allow you to perform a squat which leads to extra loading on your back putting you at higher risk of lower back injuries (Glassman 2002).
If you’re wanting to squat deeper, athletes need to be aware the deeper the squat the higher lumbopelvic stabilisation requirements of the erector spinae and rectus femoris which is shown in a study by Grosuch et al (2013). Poor strength, poor stabilisation= increased risk of injury. Poor control will cause compensations to other areas and can potentially affect the entire lower limb kinematics (Powers 2014).
Lacking ankle range of motion (ROM)?
A lot of people struggle with ankle dorsiflexion (pointing toes towards the ceiling). This ankle movement is important in the squat. If your ankle range is reduced this will prevent your knees from tracking over your feet, therefore, compensations will occur in other areas. For example your feet will pronate (rotate inwards) to allow knee movement. This will then cause hip internal rotation and hip adduction causing valgus collapse of your knees (Contereas 2013).
This is very common as there are many factors which could be restricting you ankle ROM such as tight lower leg musculature for example your gastrocnemius, soleus, anterior tibialis.
Ankle ROM can cause many dysfunctions in the squat, not just knee valgus movement but your weight will be shifted backwards causing compensations such as leaning forwards so you don’t fall backwards (Cecil 2014).
Ways to assess squat technique
Very few people will be at the end of their full hip ROM, therefore, getting your squat assessed will allow a Sports Therapist to give you an individualised strengthening and mobility programme to enable you to perform a squat to your fullest, and prevent you from injury (DeBell 2014).
You don’t have to be injured to see a Sports Therapist; they are there to also prevent injuries from occurring. We will decrease the chance of this by assessing how you squat either by appointment or at a squat clinic. Injury prevention and corrective exercises are important for everyone.
There are many ways to assess squat technique such as movement patterns, mobility and stability. Conteras (2013) first looks at movements of the hip such as hip flexion (bringing knee to our chest) to first establish whether our hips prefer being in a narrow squat or a wide squat angle. When squat technique is assessed the following is looked at.
- Keeping a straight back (don’t let the lower back curve into lumbar flexion at the bottom of the squat)
- Knees tracking over toes
- Heels remain on the ground
- No loss of balance when performing the squat
- Control throughout the eccentric (lowering) and concentric (rising) phase of the squat
- Keeping neutral head position
We want to stress the importance of correct squat biomechanics. Remember you don’t have to be injured to be assessed.
Thank you for reading, happy squatting and lets stay injury free! Any questions don’t hesitate to get in contact.
BSc Sports Therapy MSST
DeBell, R. (2014). The best kept secret: why people have to squat differently. Available: http://themovementfix.com/the-best-kept-secret-why-people-have-to-squat-differently/. Last accessed 7/4/15.
Chandler, J; McMillan, J; Kibler, B; Richards, D. Safety of the squat exercise. Available: https://www.acsm.org/docs/current-comments/safetysquat.pdf. Last accessed 15/4/15.
Contreras, B. (2013). Squat biomechanics: Butt wink- what is it, what causes it, and how can it be improved. Available: http://bretcontreras.com/squat-biomechanics-butt-wink-what-is-it-what-causes-it-how-can-it-be-improved/. Last accessed 8/4/15.
Contreras, B. (2013). 7 dilemmas solved. Available: https://www.t-nation.com/training/7-squat-dilemmas-solved. Last accessed 8/4/15.
Contreras, B. (2013). Knee Valgus (Valgus collapse), gluteus medius strengthening, band hip abduction exercises and ankle dorsiflexion drills. Available: http://bretcontreras.com/knee-valgus-valgus-collapse-glute-medius-strengthening-band-hip-abduction-exercises-and-ankle-dorsiflexion-drills/. Last accessed 8/4/15.
Cecil, A.M. (2014). Squat fix: falling backwards. The Crossfit Journal.
Cressey, E. (2014). Squats vs. Hip thrusts; which is better? Available: http://www.ericcressey.com/squats-vs-hip-thrusts-which-is-better. Last accessed 8/4/15.
Glassman, G. (2002). Squat Clinic. Crossfit Journal.
Gorsuch, J; Long, J; Miller, K; Primeau, K; Rutledge, S; Sossong, A; Durocher, J. (2013). The Effect of Squat Depth on Multiarticular Muscle Activation in Collegiate Cross-Country Runners. The Journal of Strength and Conditioning Research. 27 (9), pp.2619-2625
Powers, C.M. (2014). The influence of abnormal hip mechanics on knee injury. A Biomechanical Perspective Journal of Orthopedics.