Hamstring Strain Injuries: Lessons from Personal Experience and the Latest Research

Hamstring Strain Injuries: Lessons from Personal Experience and the Latest Research

Recently, in an effort to keep the ballooning effects of the all-you-can-eat buffet at bay during my Cricket Australia Indian tour, I ramped up my high-intensity running load. Things were going splendidly — four days of high-intensity running under my belt — until day five, when 90% of the way through a very intense interval session, I tore my hamstring.

I felt the tell-tale sensation so many of my patients describe: a sharp tearing and retraction sensation in my outer thigh while sprinting. I had to pull up immediately and iced the injury straight away. You’ll be happy to hear that I’ve since fully recovered. No longer ‘gun shy’ at my top speeds (which, admittedly, are not that fast!), my strength has vastly improved, and I’m back running at full capacity.

Having treated countless hamstring injuries through my long involvement in recreational, semi-elite, and elite sport — especially with Cricket Australia teams and the Aspley Hornets NEAFL squad — this experience gave me even deeper appreciation for how tricky these injuries can be. Hamstring strains are one of the most common injuries in running athletes, responsible for significant downtime and lost performance. Hamstring injuries have remained the most prevalent injury in professional AFL for the past 21 consecutive seasons (Orchard et al., 2013), with the average 2012 injury costing clubs over $40,000 per player!

Understanding Hamstring Injury Mechanisms

Most hamstring tears occur during the late-swing phase of running, where the hamstring undergoes rapid lengthening while producing high forces (Danielsson et al., 2020). Key risk factors include:

  • High eccentric loading demands.

  • Poor neuromuscular control.

  • Muscle imbalances (particularly hamstrings vs quadriceps).

  • Fatigue — as evidenced by my own injury, occurring late in a demanding session!

Importantly, the long head of biceps femoris is the most commonly injured muscle, partly due to its higher proportion of fast-twitch fibers and its anatomical position under stretch during running (Martin et al., 2022).

Fatigue, poor trunk/pelvic control, and sudden spikes in high-speed running are emerging as significant contributors to hamstring strain risk, particularly in field and court sports (Martin et al., 2022).

Preventing Hamstring Injuries

The good news is, hamstring injuries can often be prevented with smart training. Strengthening the hamstrings through eccentric exercises like Nordic hamstring curls and single-leg Romanian deadlifts has been shown to reduce injury rates significantly (Al Attar et al., 2017; Martin et al., 2022).

Effective prevention programs should also include:

  • Agility and trunk stabilization exercises — not just strength work (Martin et al., 2022).

  • Warm-up routines with dynamic stretching and sport-specific drills.

  • Monitoring high-speed running loads to avoid sudden spikes in intensity.

Addressing muscle imbalances is key too. Maintaining a healthy strength ratio between the quadriceps and hamstrings — and ensuring good trunk and gluteal control — promotes optimal biomechanics and reduces injury risk (Martin et al., 2022).

Recovering Well After a Hamstring Injury

A proper recovery should include:

  • Early management: Controlling swelling and pain with ice and appropriate activity modification.

  • Progressive eccentric strengthening: Integrated carefully to build resilience.

  • Functional rehabilitation: Sprinting drills, agility work, and sport-specific movements are crucial before returning to full play (Martin et al., 2022).

Interestingly, studies show athletes who follow programs that include eccentric training and trunk stability work have lower reinjury rates than those who just focus on basic strength and stretching (de Visser et al., 2012; Martin et al., 2022).

Return-to-play decisions should be made carefully. Factors like strength symmetry, absence of pain, and readiness for high-speed running should all be considered to reduce the risk of reinjury, which can be as high as 30% otherwise (Martin et al., 2022).

Final Thoughts

Even as a physio, my personal hamstring tear was a stark reminder that fatigue, progressive loading, and structured rehab are vital ingredients for both prevention and recovery. Whether you’re a weekend warrior, a professional cricketer, or just trying to beat the buffet, hamstring health is crucial.

If you’d like help strengthening your hamstrings, managing an existing injury, or optimising your running and performance, feel free to reach out. I (and my hamstrings) would be happy to help!

Till next time, Praxis what you Preach!

Backed by evidence. Trusted by athletes. Here for every body.

References

  • Al Attar, W.S.A., et al. (2017). The effectiveness of injury prevention programs in reducing the incidence of hamstring injuries in soccer players: a systematic review and meta-analysis. Journal of Physiotherapy, 63(1), 11–17.

  • Danielsson, B., et al. (2020). Mechanisms of hamstring strain injury: current concepts. Sports Medicine, 50(4), 669–682.

  • Martin, R.L., et al. (2022). Hamstring strain injury in athletes: Clinical Practice Guidelines. Journal of Orthopaedic & Sports Physical Therapy, 52(3), CPG1–CPG44.

  • Orchard, J.W., et al. (2013). AFL Injury Report 2012.

Split Squat vs Squat vs Deadlift: How to tailor your lower body training

Split Squat vs Squat vs Deadlift: How to tailor your lower body training

The age old question: What’s the best gym activity for my sport? Well – the answer should always be “it depends”. Even the same athlete playing the same sport will have different requirements at different parts of a season. Generally speaking, there are some common exercises in utilised by strength coaches when programming for athletes. The split squat, squat, and deadlift are all compound exercises that target various muscle groups and are commonly included in strength training programs. In today’s Praxis What You Preach article, we are going to breakdown the kinematic (joint angles) and inverse dynamic (joint forces from assumed joint angles) differences between these exercises. We’ll also briefly discuss what sports may benefit, but as just mentioned, the answer is “it depends”.

The Split Squat

The split squat is a unilateral lower body exercise that primarily targets the quadriceps, hamstrings, glutes, and hip stabilisers. It is a personal favourite of mine as I believe it replicates many athletic positions and helps identify any asymmetries there may be. In this exercise, you start in a staggered stance with one foot forward and the other foot positioned behind. The front leg performs most of the work, while the back leg provides support.

The Movement

  • The front knee flexes and extends, moving vertically.
  • The rear leg remains relatively stationary, providing balance and stability.
  • The hip joint of the front leg moves through flexion and extension.

What’s working?

  • The front leg experiences greater joint forces and moments due to supporting most of the load.
  • The knee extensors (quadriceps) and hip extensors (glutes) generate the majority of the force to extend the knee and hip joints.
  • The rear leg primarily acts as a stabilizer rather than generating significant force.

Sports?

The split squat is a versatile exercise that can benefit individuals participating in a wide range of sports. Running, jumping and change of direction field sports such as AFL and soccer seem to benefit well due to the asymmetrical load on the pelvis. The increased loading of the hip stabilising muscles make this a useful exercise for tennis players, volleyballers and track and field (eg triple jumpers) athletes as well.

The Squat

An absolute staple of the gym! The squat is a bilateral lower body exercise that primarily targets the quadriceps, hamstrings, glutes, and lower back muscles. For the sake of this argument, talking about a Barbell back squat. It involves descending into a squatting position while maintaining a relatively upright trunk and then returning to a standing position.

The Movement

  • The hips and knees flex simultaneously, moving in a coordinated manner.
  • The knees move forward, tracking over the toes
  • The torso tilts forward slightly, maintaining a neutral spine but a bit of flex here is fine (and biomechanical studies show you can’t not flex the spine)

What’s Working?

  • The quadriceps, hamstrings, and glutes generate force to extend the hips and knees during the ascent phase.
  • The erector spinae and other lower back muscles provide stabilization and contribute to maintaining an upright posture.
  • The knee extensors (quadriceps) experience higher forces and moments during the descent and ascent phases.

Sports?

Squats help with vertical force generation so jumping sports like basketball and volleyball are sports that would benefit. The Barbell back squat is also central in powerlifting, olympic lifting and Crossfit. Given you can load significant weights to the bar, back squats are also useful for football codes whe are required to absorb impacts during tackles.

The Deadlift

The deadlift is a bilateral exercise that primarily targets the posterior chain, including the glutes, hamstrings, erector spinae, and upper back muscles. It involves lifting a loaded barbell or other weight from the floor while maintaining proper form.

The Movement

  • The hips hinge backward, allowing the torso to lean forward while maintaining a neutral spine.
  • The knees flex to a lesser extent compared to the squat.
  • The barbell moves vertically in a straight line close to the body.

What’s Working?

  • The glutes, hamstrings, and erector spinae generate force to extend the hips and maintain a neutral spine.
  • The quadriceps contribute to knee extension.
  • The upper back muscles help stabilize the spine and prevent excessive forward flexion.
  • The lower back muscles experience significant forces and moments due to their role in maintaining spinal alignment.

Sports?

Powerlifting, Olympic lifting and Crossfit are the obvious ones that spring to mind. But tackling sports such as rugby can benefit. Given the predominance of back musculature, rowers will benefit here. Wrestlers and MMA athletes will also benefit due to the whole body nature of a deadlift.

Overall, while all three exercises involve lower body movements, they differ in terms of joint angles, muscle activation patterns, and force distribution. Understanding these differences can help tailor training programs to specific goals and individual needs. We also modify these exercises further to tailor our rehabilitation needs, In that vein, it’s important to be conscious of technique when performing these exercises to maximise their effectiveness and reduce the risk of injury.

So if you are growing stale in your lower body workouts, try and mix it up with some of the above. There are also plenty of variations of the above to alter the movement and forces even more! If you are after some help to modify your gym program, chat to us today – we are here to help!

Until next time,

Praxis What You Preach

Plantar Fasciopathy: Understanding how to heal your heel pain

Plantar Fasciopathy: Understanding how to heal your heel pain

Feel like your walking on glass in the mornings?  Those first few steps after a long period of sitting hurt the underside of your heel? Struggling to stand at the end of a long day due to your feet? If so, then you may have plantar fasciopathy, also known as plantar fasciitis. Plantar fasciopathy is a common condition that affects the plantar fascia – a thick band of connective tissue on the bottom of the foot. Plantar fasciopathy commonly affects individuals between the ages of 40 and 60, but can affect almost anyone. In this article, we will delve into the causes, symptoms, treatment options, and preventive measures to help you understand, and more importantly manage, this condition.

Causes and Symptoms

Plantar fasciopathy is often caused by repetitive strain or excessive loading of the plantar fascia, leading to microtears and inflammation. Factors such as overuse, improper footwear, high-impact activities, flat or high-arched feet, and tight calf muscles can contribute to its development. The condition is characterised by sharp pain or a dull ache on the underside of the heel or along the arch of the foot. Pain is typically worse in the morning or after periods of inactivity, and may improve with movement. Standing for long periods or walking on hard floor can also be aggravating.

Treatment Options

The treatment of plantar fasciopathy focuses on reducing pain, promoting load tolerance, and addressing the underlying causes. Physiotherapy interventions play a crucial role in managing this condition. Therapeutic techniques such as manual therapy, stretching exercises, and strengthening exercises can help relieve pain, improve flexibility, and restore foot function. Specifically, improving the windlass mechanism (a phenomena that refers to the tightening of the plantar fascia during the push-off phase of walking or running when you big toe extends). This mechanism helps distribute forces evenly throughout the foot and reduces strain on the plantar fascia. More generally, improvement of the footy intrinsics and plantar flexors more generally have been shown to reduce the severity and duration of symptoms as well.

Additionally, the use of orthotics, taping, or night splints may provide support and alleviate symptoms. Extracorporeal shockwave therapy (ESWT) and ultrasound therapy are also viable treatment options in some cases. In severe or persistent cases, corticosteroid injections or surgery may be considered, though this is usually reserved for when conservative measures have failed.

Preventive Measures

Prevention is key to reducing the risk of plantar fasciopathy starting in the first instance. If you are keen to ‘pound the pavement’ for example, then gradually increase activity levels. Avoid sudden changes in intensity or duration to prevent overloading the foot. This may mean dancing long bouts for the first time in a while, or returning to running post injury. Wear footwear that provides adequate arch support and cushioning. Understand the importance of regular stretching exercises for the calf muscles and plantar fascia.

As physiotherapy professionals, we understand that addressing the symptoms of plantar fasciopathy early is essential for providing effective care. At Praxis, effective care means arming you with adequate advice and education so you can help manage the symptoms yourself. Further, implementing appropriate treatment options and emphasizing preventive measures, we support individuals in overcoming foot pain and restoring quality of life. After all, we aim to Prevent, Prepare, Perform! So if you have heel pain that is stopping you from doing what you would like to do, discuss it with our knowledgeable team today!

Until next time – Praxis What You Preach!

📍 Clinics in Teneriffe, Buranda, and Carseldine

💪 Trusted by athletes. Backed by evidence. Here for everyone.

Understanding Sever’s Disease: A Common Foot Condition in Active Growing Children

Understanding Sever’s Disease: A Common Foot Condition in Active Growing Children

Sever’s disease, also known as calcaneal apophysitis, is a prevalent foot condition that primarily affects growing children. While not a true “disease,” it is an overuse injury that causes pain and discomfort in the heel.

Sever’s disease occurs when the growth plate in the heel, known as the calcaneal apophysis, becomes inflamed and painful due to repetitive stress and tension. This condition typically affects children between the ages of 8 and 15 who are actively involved in sports or activities that involve running or jumping. During a growth spurt, the heel bone can grow faster than the surrounding tendons and muscles, leading to strain and irritation during loading.

Symptoms and Diagnosis

The primary symptom of Sever’s disease is heel pain, usually felt at the back or bottom of the heel. The pain is typically aggravated during physical activities such as running and jumping and may improve with rest. The pain is often described as aching or throbbing and is usually located at the back of the heel or bottom of the foot. A physical examination by a Praxis Physio, combined with a review of the presenting history and symptoms, is usually sufficient to diagnose the condition. In some cases, an X-ray or MRI may be recommended to rule out other possible causes of heel pain.

Treatment and Management

The treatment for Sever’s disease focuses on relieving pain and reducing inflammation. Initially, the R.I.C.E. (rest, ice, compression, elevation) method is often recommended to manage symptoms. As many parents know, rest is easier said than done so avoiding or modifying activities that aggravate the pain is crucial. Your physio will be able to aid in planning the week’s loading to ensure symptoms are kept at bay. In some cases, heel pads or shoe inserts can provide additional cushioning and support. Exercises that stretch and strengthen the calf muscles and Achilles tendon to improve load tolerance are also provided by your physiotherapist as shown in the video above. Pain relief medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), may be prescribed in severe cases.

Prevention and Prognosis

Preventing Sever’s disease involves maintaining a balance between activity and rest. Encouraging children to warm up properly before physical activities can help reduce the risk. Additionally, the rehabilitation between bouts of physical activity will also allow for the easing of symptoms. The prognosis for Sever’s disease is excellent, with most cases resolving as the growth plate closes. Once the bones and muscles have finished growing, the symptoms typically disappear.

In summary, Sever’s disease is a common condition that affects growing children, primarily those engaged in sports or activities involving repetitive stress on the heel such as running. Recognising the symptoms, seeking early diagnosis, and implementing appropriate treatment and preventive measures are key to managing this temporary condition and ensuring a smooth recovery for children experiencing Sever’s disease. To ensure your child is back playing sports quickly, book in with the friendly and professional physios at Praxis today!

References

James, A. M., Williams, C. M., & Haines, T. P. (2016). Effectiveness of footwear and foot orthoses for calcaneal apophysitis: a 12-month factorial randomised trial. British journal of sports medicine, 50(20), 1268–1275. https://doi.org/10.1136/bjsports-2015-094986

Scharfbillig, R. W., Jones, S., & Scutter, S. D. (2008). Sever’s Disease: What Does the Literature Really Tell Us? Journal of the American Podiatric Medical Association, 98(3), 212–223. doi:10.7547/0980212

Weert, H. C., van Dijk, C. N., & Struijs, P. A. (2016). Treatment of Calcaneal Apophysitis: Wait and See Versus Orthotic Device Versus Physical Therapy: A Pragmatic Therapeutic Randomized Clinical Trial. Journal of pediatric orthopedics, 36(2), 152–157. https://doi.org/10.1097/BPO.0000000000000417

Tibialis Anterior – The missing link to pain free legs and performance?

Tibialis Anterior – The missing link to pain free legs and performance?

Shin splints? Painful knee with jumping? Recurrent ankle sprains? These are the types of injuries we fix day in and day out at Praxis Physio. There are number of recommended paths for rehabilitation in theses injuries backed by the research and our clinical experience, but has the evidence been missing something? There is some social media traction in the fitness and exercise world recently around tibialis anterior (TA) loading as a ‘cure all’ for every lower limb injury. Being the physio nerds that we are, we looked in to it for you!

The tibialis anterior is located on the front (anterior) portion of the shin (tibia) – hence the name. Its role is to lift the foot (dorsiflex) the ankle as well as provide some stability for the outside of the ankle . This action is key for movements in walking and running especially in negotiating steps and hills as the foot needs to clear a certain height before landing. It is also very important in landing from a height and changing directions rapidly, as it acts as shock absorber for the knee and ankle joints (reference).

Like any muscle or joint in the body, the TA is not without its problems. Physios are regularly confronted with patients who complain of pain and stiffness around the muscles of the shin. Such conditions may include shin splints, compartment syndrome, patellofemoral pain syndrome (aka runner’s knee) and general ankle joint pain and stiffness post ankle sprain.

As mentioned, there has been a lot of discussion lately in the strength and conditioning community about whether training this muscle can prevent or treat musculoskeletal conditions, such as the ones mentioned above. Anecdotally, training of the TA has been described several benefits. Specific athletes have explained that they have seen improvements in vertical jump height, running speed, running stamina and squat depth. From a prevention and treatment point of view, it has been said that training the TA has helped improve symptoms associated with knee pain, ankle pain and shin splints. Also let us not forget, that from an aesthetics point of view, a strong and bulky looking TA does make our legs look more attractive, as bodybuilders would argue.

Unfortunately, the scientific community has not provided strong evidence that training the TA can aid in affecting the above musculoskeletal pathologies, or attain the performance benefits. So what do we know from previous scientific literature? Well, Munoz et al (2015) describes the tibialis anterior as key during an efficient gait cycle as well as being critical for balance control. Furthermore, an increase in strength of the TA helps greatly reduce the risk of falling. Maharaj et al (2019) confirms that during walking and running , TA’s tendinous tissue absorbs energy during contact and controls foot position during swing.

The proposed mechanisms to aid in athletic performance include:

  1. Increased ankle stability: Strong tibialis anterior muscles provide better stability to the ankle joint during jumping movements. This stability allows for improved force transmission from the lower leg to the foot, enabling athletes to generate greater power and maintain proper alignment during takeoff and landing.
  2. Enhanced dorsiflexion range of motion: Adequate dorsiflexion range of motion is essential for optimal jumping performance. Strengthening the tibialis anterior helps to improve flexibility and mobility in the ankle joint, allowing athletes to achieve a greater degree of dorsiflexion during the pre-jump phase. This increased range of motion enables a longer and more powerful push-off, resulting in higher jumps.
  3. Improved jump height and explosive power: The tibialis anterior plays a significant role in generating propulsive force during the takeoff phase of a jump. By strengthening this muscle, athletes can produce a more forceful and efficient push-off, leading to increased jump height and explosive power. The ability to generate greater force through dorsiflexion contributes to a more powerful and effective jump.
  4. Injury prevention: Weak tibialis anterior muscles can contribute to imbalances in the lower leg, potentially leading to various conditions such as shin splints or ankle sprains. Strengthening this muscle group helps to maintain proper muscle balance around the ankle joint, reducing the risk of injuries that could hinder jumping performance.

So if we are to believe TA holds the key to athletic performance and injury mitigation, how do we unlock it?

To strengthen the tibialis anterior, physiotherapists often prescribe specific exercises that target this muscle, such as toe raises, resisted dorsiflexion exercises, or using resistance bands to provide resistance during dorsiflexion movements. These exercises should be performed in a controlled manner and progressively increased in intensity to promote muscle strength and endurance. Below you see variations on how you can load the TA and progress and regress it respectively. Remember that we need to treat the TA like any other muscle we are wanting to train – progressively overloading it!

As Physiotherapists, we greatly value and adhere to evidence-based practice, however one could argue that this particular muscle has not received the scientific study treatment it rightly deserves. So if you are having some lower leg issues, or haven’t quite got that bounce you are wanting, come and chat to one of our friendly and knowledgeable staff. We can do a full assessment and put the spring back in your step!

Until next time, Praxis what you preach!

Prevent. Prepare. Perform

References:

Maharaj JN, Cresswell AG, Lichtwark GA. Tibialis anterior tendinous tissue plays a key role in energy absorption during human walking. J Exp Biol. 2019 Jun 4;222(Pt 11):jeb191247. doi: 10.1242/jeb.191247. PMID: 31064856.

Ruiz Muñoz, M., González-Sánchez, M. & Cuesta-Vargas, A.I. Tibialis anterior analysis from functional and architectural perspective during isometric foot dorsiflexion: a cross-sectional study of repeated measures. J Foot Ankle Res 8, 74 (2015). https://doi.org/10.1186/s13047-015-0132-3

Shin Splints | Physio Guide to Medial Tibial Stress Syndrome

Shin Splints | Physio Guide to Medial Tibial Stress Syndrome

SUMMARY

  • Shin splints are essentially an overuse injury
  • Numerous factors contribute to symptoms but mainly involving the poor control of force through the lower limbs
  • Important to stop symptoms to avoid developing stress fractures, which require lengthier time away from activity
  • Corrective strengthening exercises, relative rest, and workload management all seem to be treatment mainstays
  • Physiotherapy has a significant role to play in getting back to running and sport
Mid Potion Achilles Tendinopathy Location

SHIN SPLINTS

Shin splints, or as it’s referred to as in the literature, medial tibial stress syndrome (MTSS), is a common injury seen in the recreationally active and army populations. Symptoms typically consist of an aching pain to the lower medial (inside) part of the shin, that can be sharp when running or when inflamed. There can also be some pain and stiffness when you first walk around in the morning, or when you first start your activity.

Risk Factors:

Over 100 potential intrinsic risk factors of MTSS were identified in a recent systematic review [1] involving 21 different studies. Of those risk factors, nine were identified as having a moderate to strong occurrence in clinical practice. Out of these nine, the risk factors that result in the greater loads on the body (such as body mass index) or poorer acceptance of load with running were the most important.

A number of range of motion parameters were also identified. For example, larger plantar flexion range of motion (the movement of pointing your foot down) was identified. It has been hypothesized that the increased plantar flexion results in a greater likelihood of the individual landing on their forefoot rather than their rearfoot while running, possibly increasing the strain on the rear inside leg (posteromedial tibia). Forces on the inside of the shin bone explain the why pain may be present in that area.

Treatment:

Most people tend to simply rest which may decrease symptoms in the short-term, but it doesn’t address the direct cause! The condition is very commonly seen in recreational runners and not as much in your higher-level athletes. Why is this? It’s quite simple! As mentioned in our previous running blogs, the adherence to well-planned running workloads is what separates recreational runners from the competitive or non-injured. Planned training leads to adequate adaptation of the body to the demands placed upon it.

One of areas patients with shin splints focus on is poor “foot posture”. It is very common to hear the same old story, “I have shin splints because my feet are flat, I need orthotics to correct that”. The biggest problem with that approach is that not a lot of people realise that the reason that they are flat footed is not necessarily because of a defect in their feet! It may be because they have strength and control of their hips which is in turn is causing over pronation or flattening of their feet.

The diagram below demonstrates that perfectly!

As the hips cannot stay level during running, this may cause the knees to fall inwards and in turn causes pronation or flattening of the foot. Then, voila! You have increased tractional stress on the medial aspect of the tibia/shin bone. Yes, there is some evidence that poor foot posture can cause the problem, but only in combination with extrinsic risk factors such as over-training and rapid increases in workload.

Poor hip control and strength is also a precursor for many other musculoskeletal conditions such as lower back, hip, knee and Achilles pain. So if we could reduce the risk of these outcomes occurring in the future, why wouldn’t we try!

It is possible that MTSS is a condition where the simple treatment of rest is enough to reduce symptoms. Until proven otherwise, relative rest remains the number one treatment option for reducing your symptoms. However, If addressed early, MTSS can be managed with the combination of targeted strength routines, running workloads, manual therapy and ensuring adequate recovery time between training sessions.

If you are experiencing shin splints or are looking to prevent such injuries from reoccurring, please feel free to book online or give us a call (07) 3102 3337. You’ll receive an in depth assessment and treatment plan to help you achieve your goals and run better for longer!

Till next time, Praxis what you preach.

The Praxis Team.

PREVENT | PREPARE | PERFORM

Images:

The above images are owned by the “Trainer Academy (https://traineracademy.org/) ” and used in this article with thanks.

References:

[1] Winkelmann, Z., Anderson, D., Games, K., & Eberman, L. (2016). Risk factors for medial tibial stress syndrome in active individuals: An evidence-based review. Journal of Athletic Training, 51(12), 1049-1052. 10.4085/1062-6050-51.12.13