The “Z” angle

As we know how important it is, for runners, to maintain optimal running form to maximize efficiency and to prevent injury. One method to optimize running form for injury prevention is to maintain and appropriate Z angle.

The Z angle is formed by analyzing running from side and measuring joint angles at your hip and ankle. The z angle is the angle formed by your hips and ankles when your foot is on the ground, just prior to a terminal stance.

How to find ‘z’ angle?

• Obtain a still photo of you running, shot from the either side. Your back foot should be on the ground, but just about to leave the ground in terminal stance. Your front leg should be up in the air and flexed in front of you. ( You’ll need a friend or PT to take the video of you running on a treadmill.)
• Once you have the photo, draw a line through your hip joint that is parallel to the plane of the top of your pelvis.
• Draw a line along your stance leg extending down from your hip to your ankle.
• Draw a line from your ankle joint, through your foot, and to your toes.
The three lines you have drawn should form the shape of the letter “Z.” This is your Z angle.Runner Ahmedabad india
The optimal Z angle should show that your hip extension range of motion is equal to your ankle dorsiflexion range of motion. Your letter Z should look like a symmetrical letter. If your letter Z is altered in any way, it could mean that you have some running gait deviations that may need to be addressed to optimize efficiency and to possibly prevent injury.

Deviations and treatment :

If ankle of dorsiflexion is less, then athlet’s Z angle will show bigger angle at ankle than at hip. This means
• Gastro and soleus are tight, and
• Tebialis anterior is weak

The correction regime includes,
• Stretching of gastro and soleus, and
• Strengthening of tebialis anterior
If hip extension is less, this means
• Hip flexor and rectus femoris tightness and
• Hip extensors weakness
The correctional regime includes,
• Stretching of hip flexors and rectus femoris
• Glute strengthening.


free full text :


1. Ferber R, et al. Suspected Mechanisms in the Cause of Overuse Running Injuries: A Clinical Review. Athletic Training. 2009.

2. Kim S and Yu J. Changes of Gait Parameters and Lower Limb Dynamics in Recreational Runners with Achilles Tendinopathy. J Sport Sci Med. 2015. 284-89.

3. Schmitz A, et al. Do Novice Runners Have Weak Hips and Bad Running Form? Gait Posture. 40(1). 2014. 82-6.

image courtesy:,


Scapula stabilisation

Thoughts on Scapula exercise

Scapula exercises are very common and usually a needed to any shoulder rehabilitation or corrective exercise program.    No program is right for everyone!  Here are of scapular exercises that we thought would good to discuss.


1) Pinch Your Shoulder Blades Together :

Pinch your shoulder blades , Squeeze your scaps together.  Retract your shoulders back.  These are common coaching cues given during scapular exercises.  The goal of these concepts is to get into better posture and set your scapula  in correct postion ,ultimately resulting in  better movement patterns along with better posture  when performing exercises.

The classic example is Upper Body Cross Syndrome of forward head, rounded shoulders.

scapulohumeral rhythm requires a sequence of shoulder and scapular movement simultaneously.  Pinching your shoulder blades together is essentially contracting your middle trapezius to fully retract your scapula and then move your arm.  While this is not nearly as bad on shoulder mechanics as lifting your arm . it does not have good advantage to lift your arm in a fully retracted position. While fully retract the scapula  which is essentially performing and isometric trapezius contraction, you are likely to limit the normal protraction and upward rotation movement  that occurs  during arm elevation and movement.

If the milestone  of this to give cue for  improve posture and improve mechanics while exercising the arm, maybe a better cue would be to instruct thoracic extension.

Think about , you can still have a very kyphotic and rounded thoracic spine and retract your scapula, it’s. Very difficult to perform , but the goal is to really get your thoracic spine extended.

2) Mobility and Strength to Improve Scapular Symmetry.


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Introduction to core subsystem

Muscles don’t work alone to create movement. They work together in synergies to create coordinated movements. Here we’ll identify the four muscle subsystems, discover how these synergies work together, and how to select exercises for developing optimal performance.

Introduction :

The purpose of this article is to provide a brief overview and definition of the four subsystems within the human body , how they contribute to human movement system .
Muscle does not work in isolation. This simplifies movement by allowing muscles and joints to operate as a cohesive unit. For instance, during the simple act of shoulder extension, the latissimus dorsi, teres major, and posterior deltoid all work together as a unit to perform the movement pattern.

Local vs. Global Musculature:

Looking at the muscular system more closely, systems that enable our bodies to distribute forces efficiently. These systems include the local muscular system, known as the stabilization system, and the global muscular system, which referred to as the movement system.

. The local muscular system muscles provide stability and support during joint motion. Where as they are usually located in close to the joint which makes them ideal for increasing joint stiffness and stability, such as the transverse abdominis, multifidus, and pelvic floor.

On the other hand, the global muscular system is responsible for movement of the trunk and extremities, and primarily consists of large superficial musculature, such as the rectus abdominis, latissimus dorsi, and external obliques.


The human body consists of four common muscle synergies:

• Lateral subsystem,
• Deep longitudinal subsystem,
• Posterior oblique subsystem,
• Anterior oblique subsystem.

These subsystems allow for an easier description and review of functional anatomy. The human body simultaneously utilizes all four of these subsystems during activity of daily routine.

Figure 1

The lateral subsystem (Figure 1) is comprised of the gluteus medius, tensor fascia latae, adductor complex, and contralateral (opposite) quadratus lumborum. The lateral subsystem is implicated in frontal plane stability and is responsible for pelvo-femoral stability during single-leg movements such as in gait, lunges, or stair climbing. The ipsilateral (same side) gluteus medius, tensor fascia latae, and adductors combine with the contralateral quadratus lumborum to control the pelvis and femur in the frontal plane.

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Figure 2

Deep Longitudinal Subsystem :

The deep longitudinal subsystem (Figure 2) is comprised of the erector spinae, thoracolumbar fascia, sacrotuberous ligament, and bicep femoris. The deep longitudinal subsystem helps to stabilize the body . More accurately , it provides force transmission longitudinally from the foot and ankle to the trunk and vice versa. The dominant role of the deep longitudinal subsystem is to control ground reaction forces during gait motions .

Core subsystem

Figure 3

Posterior Oblique Subsystem:

The posterior oblique subsystem (Figure 3) is comprised of the gluteus maximus, latissimus dorsi, and thoracolumbar fascia. The posterior oblique subsystem works synergistically with the deep longitudinal subsystem which distributing transverse plane forces . The gluteus maximus and latissimus dorsi attach to the thoracolumbar fascia, which connects to the sacrum. The fiber arrangements of these muscles run perpendicular to the sacroiliac joint (SIJ). Thus the contralateral gluteus maximus and latissimus dorsi contract they create a stabilizing force for the SIJ.

Core subsystem

Figure 4


Anterior Oblique Subsystem:

The anterior oblique subsystem (Figure 4) is comprised of the internal oblique, external oblique, adductor complex, and hip external rotators. Likewise, the posterior oblique subsystem this system also functions in a transverse plane orientation, only from the anterior portion of the body. When we walk our pelvis must rotate in the transverse plane in order to create a swinging motion for the legs. This rotation comes in part from the posterior oblique subsystem posteriorly and the anterior oblique subsystem anteriorly.


Stay tune with us for next part : integrated exercise for core subsystem.


References :

1) Stability of the lumbar spine. A study in mechanical engineering. Acta Orthop Scand Suppl. 1989;230:1-54.

2) Clark MA. Lucett SC. Sutton, BG. NASM Essentials of Corrective Exercise Training 1st Edition Revised. Burlington, MA: Jones and Bartlett Learning; 2014.

3) image courtesy: Brian Sutton MS, MA, NASM-CPT, PES, CES ,