Welcome to a new branch of Evolve Fitness Lab blogs called THERE’S SCIENCE IN THIS S—. I recently resumed my educational journey. This time in the form of grad school. I’m working on receiving my Masters in Applied Exercise Science with an emphasis in Strength and Conditioning.
So if you see me like this behind the desk, don’t worry. I’m just going through school stuff. Tell me to go get a coffee or a beer to relax.
The blogs that I am posting for There’s Science In This S— (TSITS) are actually my work from my classes. This first piece is an analysis of the deadlift I did for my current class, Kinesiology II. The assignment was to do a video of a lower body multi-joint movement, analyze it, and break down the movement and plane of motion of the thorax, pelvis, knee, ankle, and foot. I hope you all enjoy!
- Sagittal Plane: Divides the body into left and right halves. Flexion and extension occur along the plane.
- Posterior Chain: musculature towards the back of the body (Anterior refers to the front half of the body)
- Thorax: part of the body between the neck and abdomen (middle back)
- Pelvis: the hips
- Concentric: A muscle action where the muscles shortens because of a stronger contraction than the resistive forces.
- Eccentric: A muscle action where the muscle lengthens because the contraction is less than the resistive forces.
ANALYSIS OF THE DEADLIFT
Dartfish Video: Deadlift. https://dartfi.sh/QCMnG5v1Dwg
The Deadlift is a multi-joint lower body pulling movement. The posterior chain is primarily used to move into extension while staying in the sagittal plane. The muscles that are concentrically used for this type movement are the glutes, hamstrings, and quadriceps. The spinal erectors, rectus abdominis, obliques, transverse, and the musculature of the upper back are used isometrically to put the spine into extension and protect the lower back during the movement (Rippetoe, 2011). The musculature of the upper arms and forearms are also used isometrically to hold the bar in place while performing the lift.
When preparing for the deadlift you should start with your feet; Having your feet around hip with apart depending on your bone structure is ideal. The bar is then placed over your metatarsals about 1 inch away from your shin. Flexion happens through the pelvis and knee when hip hinging into your starting positioning. Grab the bar and pushing your chest towards the bar while slightly pulling up to add tension results in extension through the thorax. Once in that position breathing into your stomach and then bracing around that breath will give you structural rigidity to perform the movement efficiently. Isometrically using the core and spinal erectors to keep the thorax in extension and protecting the spine will prevent injury. To activate the glutes drive you knees into your arms and flex your toes and feet like you are grabbing the ground to create foot stability. Driving forces will begin the from hips.
All of your force comes from your your hips. When performing the deadlift drive the ground away from you while the thorax, pelvis, and knees go into extension and the ankles go through dorsiflexion. The hips and shoulders should also be rising at the same time. The glutes, hamstrings, and quads are working through the extension. The thorax stays in extension through the entire lift by isometric contraction of the core, latissimus dorsi, rhomboids, and the erector spinae. Do not hyperextend the back while performing this lift. A mistake people can make is lifting too much and not having the core and back strength to stabilizing the spine, cause it to go into flexion during the lift. Keep the bar as close to you to reduce the moment arm of the barbell. Keeping the bar close decreases the resistance of the external load and keeps the back protected (Brown et al., 2016). When the weight is displaced in front of you lengthening the moment arm your spinal erectors will have to fight harder to keep a neutral spine. A long moment arm from the bar increases the chance for injury. Your feet should be planted on the floor through the entire lift.
Finished Position/Full Extension
While standing the glutes should be squeezed, the shoulder blades retracted, and the core braced. Knees, pelvis, and thorax are fulling extended. When returning to the ground the same musculature is used eccentrically. The pelvis, and knees will go into flexion. The ankles will go into plantar flexion. Initiating the eccentric movement with the hip hinge bringing the bar back down to the ground. The thorax stays in extension throughout the movement again with isometric contraction through the core and that back. This continues to protect the spine through the down phase. Ending in your starting position.
|Movement||Plane of Motion|
|Foot||No inversion or eversion of the foot. However, there is contraction of the bottom of the foot through the toes occurring during the lift.||N/A|
Biel, A. (2015). Trail guide to the body: a hands-on guide to locating muscles, bones, and more (5th ed.). Boulder, CO: Books of Discovery
Brown, L.E. Camara, K.D. Coburn, J.W. Costa, P.B. Dunnick, D.D. Galpin, A.J. (2016). An examination of muscle activation and power characteristics while performing the deadlift exercise with straight and hexagonal barbells. Journal of Strength and Conditioning Research, 30(5), 1183-1188.
Rippetoe, M. (2011). Starting strength: basic barbell training (3rd ed.). Wichita Falls, TX: The Aasgaard Company.