Kinematics and lifting shoes

ABSTRACT

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Kinematic changes using weightlifting shoes on barbell back squat.

Sato, K, Fortenbaugh, D, and Hydock, DS. 

J Strength Cond Res 26(1): 28–33, 2012

—The purpose of this study was to validate a higher degree of foot segment angle by wearing the weightlifting (WL) shoes and to determine the kinematic differences between WL shoes and running shoes during the barbell back squat. College-aged individuals volunteered to participate in this study (N = 25). After warm-up, subjects performed 60% of 1RMbarbell back squat. Reflective markers were placed on lower extremity joints and end of the bar to create segments to analyze kinematics of the barbell back squat from a 2-dimensional view.

Three separate repeated measure analyses of variance were used at p = 0.05. Results showed that there was a difference between the footwear conditions; foot segment angle of 3.5_ (p , 0.05) and trunk lean of 22 mm (p , 0.05) were captured when wearing WL shoes. However, thigh segment peak flexion angle was not statistically different (p = 0.37). Wearing WL shoes seems to be beneficial in reducing the overall trunk lean, because this position is believed to reduce the amount of shear stress in the lower back area. Back squat with WL shoes also increased foot segment angle and possibly contributes to greater muscle excitation in knee extensors. Weightlifting shoes did not help reach thigh segment closer to horizontal as compared with the running shoe condition. It is recommended that WL shoes be used by those who are prone to displaying a forward trunk lean and who aim to increase knee extensor activation.

    Hey everyone! Hope everyone is having a good and safe time getting ready for the open coming up. This post will be looking specifically at the Barbell back squat and how weightlifting (WL) shoes can help your performance.

    It is well known throughout literature and the gym that (WL) shoes can have a positive benefit on your Olympic weightlifting workouts and other exercises requiring full range of motion of the entire body. The article that I chose to look at this month describes the effects of how the WL shoe does just that. The National Strength and Conditioning Association released a statement on principles to achieve optimal squat technique. The principles include the following; 

  1. descending in a controlled manner until the thighs reach at least parallel to the floor 
  2. keeping the shank segments (shins) close to vertical to reduce shear on the knee joint 
  3. keeping the feet in place and flat on the floor
  4. maintain a normal lordotic  posture with the torso as close to vertical as possible to minimize shear stress on the discs

To help with adhering to the above principles the International Weightlifting Federation suggests the use of WL shoes. But what do they actually do?

    The purpose of this study was to determine the kinematic differences in 1) anterior displacement of the barbell and posterior displacement of the hips (Trunk Lean Displacement) 2) peak flexion angle of the thigh segment and 3) foot segment angle, between WL shoes and athletic shoes. The study looked at 25 participants from intercollegiate athletic teams with an average age of 20.6 years. They have had 5-7 years experience with the barbell back squat. The researchers then attached markers to the toe, ankle, knee, hip and barbell, which the cameras used to track the movement. The participants lifted 60% of their self-reported 1RM. Varied squat speed is known to alter squat kinematic significantly, therefore a lighter load was necessary to match all subjects squat speed. For each squat rep, the participants were required to squat to “roughly” parallel (I hate that they did that). Let’s keep in mind that these people are not competitive lifters. They were not required to squat to depth because I can only speculate the researchers wanted to see if these guys would instinctively change their squat depth because of the WL shoes. They performed 2 sets (1 set for each footwear) of 5 reps; the 3rd and 4th reps were used to average the calculations. A rest period was given between each of the trials. 

    Okay, what did they find from the data analysis? Well if we look to the three variables they described above. 

  1. Trunk Lean Displacement – a significant difference was observed. Less trunk lean was evident while wearing WL shoes a 22 mm difference. The whole idea behind decreasing trunk lean is to minimize the risk of disc injury by minimizing shear forces. Therefore, the WL shoes did just that!
  2. Peak Thigh Segment Flexion Angle – no statistical significance was observed. Participants squatted to 20.35° ± 10.13 with regular shoes and 20.94°± 10.19 with WL shoes. Again, they were only told to squat “roughly” to parallel. No coach or judge told them when to stop, I believe internal cues told them when to stop and begin to stand again. The researchers noted that adequate mobility and training experience/coaching is needed to reach appropriate squat depths.
  3. Foot Segment Angle – a significant difference was found between angles at the ankle between WL shoes and regular shoes. A 3.5° difference was found. So for those who lack ankle mobility, WL shoes do help!

From the above findings you can interpret that wearing WL shoes can benefit everyone, especially people who are new to squatting, lack ankle mobility and have previous experiences with low back pain. From personal experience my ankle mobility is borderline Gumby, I do not have or ever had low back pain and I am not new to squatting. However, did I notice a difference when I bought my first pair of WL shoes? Hells yes! I am way more comfortable in the bottom, I can handle more weight especially overhead and I don’t have to strain my focus on keeping my torso upright. At the end of the day I support the use of WL shoes. Can you get away with not wearing them? Yes. But you do wear them you will look sick and lift heavier weight and who doesn’t want that?

 

Safe and Happy Lifting!

- Dr. Young

Crossfit Bytown