The Deadlift

The deadlift is one of the most fundamental and misunderstood lift that is often over looked due to the dangers associated with improper lifting technique. It is important to every able bodied person to learn proper lifting technique and strengthen those muscles involved in proper biomechanics while lifting an object from the ground due to its common occurrence. This is why the deadlift is so fundamental and why its implementation is so important for everyone. The deadlift is a very basic lift and is very easy to teach however it is important to stress perfect execution of the lift no matter the weight.

Technique and phases

To perform the conventional deadlift with a barbell the lifter will squat down with the bar over the balls of their feet to appropriate height in order to grip the barbell on the floor with feet around shoulder width or slightly closer. The most common grip is an alternated one with one hand being supinated and the other being pronated. The lifter should focus on keeping their back flat or slightly arched.

The lifter should be in a position where his or her back is around 45 degrees in respect to the floor.

Once the lifter is in this starting position they are ready to begin the lift. The deadlift can be broken down in three phases. The first phase is mainly knee extension with slight hip extension. Use the quadriceps (Rectus femoris, vastus intermedius, vastus lateralis, and the vastus medalis) and hip extensors (Biceps femoris, simi-tendonosus, simi-membranosus, gluteus maximus, and gluteus medius) to initiate the movement. It is imperative to focus on contracting the spinal erectors (iliocoastalis thoracis, longissimus dorsi, spinalis dorsi, and iliocostalis) to avoid rounding the back which would significantly increase sheer forces on the vertebrae which can lead to stretching ligaments, pulling the vertebrae apart, and muscle tears. It is also important to contract the antagonist muscles of the spine (Rectus abdominis, External oblique and internal oblique abdominals) to protect the spine. It is recommended to exhale during the concentric phase to avoid the Valsalva maneuver, which greatly increases blood pressure and can lead to syncope.

The second phase is simultaneous knee and hip extension. The hips are extended up and forward with the bar coming in contact with the thigh but should have very little drag force just gliding up the thigh. It is critical to keep the bar as close to the body through out the lift to reduce the moment arm of resistance which will decrease the amount of force needed to lift the barbell. The bar should always travel in a straight line which decreases the distance it is moved which will reduce the work being done.

The third and final stage is hip extension dominated. The lifter will extend their hips to a neutral position completing the lift in an erect standing position.

A common mistake is to hyper extending the back, which leads to an increase risk of injury due to sheer forces. It is also important to realize that the force needed to produce work is far greater than the weight on the bar. For example when deadlifting 135 pounds one must also take into account the resistance moment arm, force moment arm, and the body weight of the segments being moved. So the 600 newtons of force needed to move the 135 pounds is far greater than just 600 newtons.

Biomechanical Principles

It is very important to realize the biomechanical principles involved in the deadlift to insure the lift is performed safely and efficiently. With any movement from the ground gravity is always a factor. One must produce enough force to counter act gravity’s pull. Another very important principle is moment arms and how manipulating them can put a lifter in a more advantageous position allowing more weight to be moved. This is why it is so important to keep the bar as close to the body as possible without creating drag force on the shin or thigh. The shorter the resistance arm is the less work needed to move the bar. Compression and sheer forces are important principles to limit especially the sheer force while lifting. This is done by not rounding the back and keeping a slight arch or flat back through out the lift. The lifter should lock his or her back in extension using their spinal erector muscles throughout the lift.

Velocity (Distance/Time), work (force × distance), force (mass × acceleration), and power (work ÷ time) are all inter- related principles that affect the performance of the deadlift. The velocity of the bar should be high and in a straight line through out the lift, yet there is a trade off between the velocity of the bar and the level of force exerted; this is known as the force velocity curve. They are inversely related in the since that as the force goes up the velocity goes down. The average lift time of a maximal lift is around 2 seconds. The lifter should strive to minimize the amount of work needed to perform the lift by keeping the bar path short and straight. A lifter with long arms and a short torso is perfect for deadlifting due to the reduced work needed to perform the lift. These types of people are considered to have good levers, while those with short arms and long torsos are at a disadvantage.

The human body is composed of mostly third class levers which are great for range of motion but bad for maximal strength. In the deadlift however since there are multiple joints and muscles acting at once the body turns into a second class lever.

Risk of Injuries

There are risks of injury while deadlifting like there are with any other exercise one might perform. Some injuries that may occur while deadlifting is lumbar hernias, slipped discs (lumbar), sprains, and muscle tears including the biceps while using an supinated/pronated grip. The vast majority of injuries happen due to poor technique which puts the body in a compromised position to efficiently lift the weight; so the lifter will forgo form and tries to muscle the weight up. Even with perfect technique one could still sustain injuries due to muscle imbalances and inflexible muscles. The most common injury that is not associated with improper technique is bicep tears in the hand that is supinated with the alternated grip. Some of the ways to prevent these types of injuries are to use ergonomics such as a lifting belt and lifting straps. The lifting belt is a highly debated tool used by some individuals during lifts to increase intra-abdominal pressure which will help better support and protect the spine. The argument of the people who support the use of the lifting belt is that it protects lifters from spinal injuries. The argument for the individuals that appose the use of a lifting belt say that using a belt is building dependence and weakening the muscles of the core. The lifting belt has its place in weightlifting but is recommended that it should only be used on maximal lifts. The lifting straps are also a controversial tool but not to the extent of the lifting belt. The lifting straps are wrapped around the wrists and then wrapped around the bar reducing the amount of hand strength needed to move heavier loads. The arguments are the same for the lifting straps. The supporters say they reduce injuries by allowing lifters to use a double pronated grip and those who oppose there use say it creates a weakness. Footwear is also an important aspect to the deadlift because the lifter needs to have good stability while lifting. Running shoes and other soft soled shoes are bad for deadlifts because they create an unbalanced lifting surface. The best types of shoes are no shoes at all, but a hard soled shoe works too. The reason wearing no shoes is so advantageous is that there is no more natural way to lift. You are closer to the ground and there is no more stable surface than the floor under your feet.

Improved Performance

The deadlift can be improved in many different ways. The most common of ways are the use of ergonomics such as lifting belts, straps, chalk, and footwear. These tools have there place but what if improved performance is what the goal and not dependence on these aids; one might convert their technique from conventional to sumo. Sumo technique is when the lifter widens their legs and has their arms on the inside of their thighs with their feet angled so they are pointed out towards the plates. The lifter will be in a more erect spinal position limiting the amount of sheer force undergone by the L4/L5 lumbar. McGuigan& Wilson (1996) found that sumo lifters were far more vertical during their lifts than that of the conventional lifters.

References

1. Cholewicki, J., McGill, S. and Norman, R. (1991). Lumbar Spine Loads During the Lifting of Extremely Heavy Weights. Medical Science Journal of Sports Exercise. 23, 1179- 1186.

2. Faley, K. (1995). Analysis of the conventional Deadlift. Strength & Conditioning, 55-57

3. Floyd, R. (2007). Manual of structural kinesiology. New York, NY: McGraw-Hill

4. Gotshalk L. (1985). Analysis of the deadlift. NSCA Journal, 73-78

5. Graham, J. (2000). Exercise: Deadlift. Strength and Conditioning Journal, 22(5), 18-20

6. Hall, S. (2007). Basic biomechanics, fifth edition. New York, NY: McGraw-Hill

7. McGuigan, M.R.M., & B.D. Wilson (1996). Biomechanical analysis of the deadlift. Journal of Strength and Conditioning Research, 10(4), 250-255

8. Piper, T. & Waller, M. (2001). Variations of the deadlift. Strength and Conditioning Journal, 23(3), 66-72

9. Schenk, R. (1995) Prevent low back injury with the prone press up. Strength and Conditioning Journal,17, 32-33

10. Schwarzenegger, A (1985). Encyclopedia of Modern Bodybuilding. New York, NY: Simon and Schuster, inc.