Inside This Issue
- Neuromuscular Capabilities in Top-Level Weightlifters and Their Association with Weightlifting Performance
- Maximal Isometric Force in the Start of the First Pull Exhibits Greater Correlations with Weightlifting Performance than the Mid-Thigh Pull Position in National and International Weightlifters
Study: Neuromuscular Capabilities in Top-Level Weightlifters and Their Association with Weightlifting Performance
What are the capabilities that underpin weightlifting performance? What, if any, performance indicators discriminate higher from lower-level athletes?
Introduction
Underpinning weightlifting performance are several physical capabilities that athletes must possess to achieve the highest levels in sport. These include coordination, mobility, muscular hypertrophy, muscular strength, and muscular power. Of these characteristics muscular power and technical execution emerge as discriminators of high-level performance. At the highest level all athletes have excellent mobility, muscular strength, and are near the top of their weight classes in terms of lean body mass and hypertrophy development. Therefore, amongst top level competitors what explains the top three performers from the rest of the pack?
Early work by Garhammer explored the power outputs expressed by elite level athletes in competition (1). This revealed high power outputs in the second pull of the snatch and clean as well as the jerk exercise in elite competitors. Since then, coaches and scientists have looked for proxy measures to correlate with performance which do not induce as much fatigue as heavy classic lifts. Vertical jumps have emerged as a viable test to examine capabilities and demonstrate strong correlations with performance (2,3). Interestingly, where early studies showed jump height to be a major predictor of performance, later studies showed other aspects of jumping to be more important. Metrics such as jump height and propulsive impulse may be better determinants of weightlifting performance than jump height alone (4,5). For these reasons, this study attempted to determine the neuromuscular capabilities of high-level weightlifters and how they related to performance.
Purpose
The primary aim of this study was to examine the relationship between maximal strength, jumping abilities via the countermovement and squat jump, with weightlifting performance in the classic lifts. They proposed that the greater the weightlifting abilities the stronger the correlations between measured variables.
Methods
Subjects
13 international level Spanish weightlifters (6 men and 7 women) participated in the study. Men snatched an average of 141 kg and clean and jerked 171 kg whereas women snatched 81 kg and clean and jerked 100 kg respectively. The weight classes ranged from 45kg (female) to 89 kg (male). With those numbers in these classes, it represents high-level elite liters for this study.
Methods
This study was conducted in conjunction with the preparation for the world championships and data was collected around normal training procedures enhancing it’s ecological validity. Two types of vertical jumps were complete. The first was a squat jump which consisted of squatting down to 90° of knee flexion and jumping with no countermovement. Next, subjects completed a countermovement jump with a self-selected depth. Both jumps were completed with a dowel rod placed on the upper traps to remove the arm swing. Following this both the snatch and clean and jerk were maxed in a mock competition format with a brief rest between lifts to mimic competition demands. In a later session but within the two-week window athletes completed maximal front and back squats in a progressive manner.
Data was presented as mean and standard deviation. To assess correlations a Pearson’s r was generated for each comparison followed by a linear regression to determine the contributions of each measured variable to competition performance.
Results
Squat Jump
Peak power and propulsive net impulse demonstrated nearly perfect correlation with weightlifting performance. Whereas jump height showed strong to very strong correlations.
Countermovement Jump
Peak power and propulsive net impulse demonstrated nearly perfect correlation with weightlifting performance/ Whereas jump height showed strong to very strong correlations.
Front Squat and Back squat
Both showed nearly perfect correlations with performance.
Men and Women
Both men and women showed nearly perfect correlations of strength exercises to performance. However, women’s values were slightly lower than men’s (r=0.92-0.95 vs 0.84-0.98). Both groups demonstrated that countermovement and squat jumps propulsive net impulse were related to performance, but the other metrics were not.
Discussion
Along the lines of previous research, strength exercises were strongly correlated with weightlifting performance. What provides novel insight from this study was the addition of force-time metrics from the squat jump and countermovement jump. By examining additional metrics outside of jump height coaches and practitioners can gain insight on how athletes may be developing across the training periods and if training interventions may be necessary.
Its well documented that weightlifting have hops. You can see evidence of this in Shane Hammonds back flip while weighing 160kg and the legendary jumping abilities of Yuri Vardanyan. It’s not uncommon for weightlifters to jump anywhere from 40-70 cm and have high absolute and relative peak power. These metrics are easily trackable and can be derived from a switch mat or with a mobile phone. However, how these athletes jump may reveal additional insights into how to structure training and what special exercises to include. This study used both squat jumps (no stretch shortening cycle) and countermovement jumps (with a stretch shortening cycle) to examine performance. Typically, squat jumps are associated with max strength whereas countermovement jumps are associated with elastic abilities in conjunction with max strength. Over time jump height tends to level off and further increases become more difficult. At that point looking at underlying metrics of how athletes jump may be more important. In this study they examined net propulsive impulse which showed greater relationship to weightlifting performance than jump height alone. Impulse is the product of force times time and necessary in weightlifting because of the brief time period to move the mass from the floor to its respective position in the lift. By increasing the net impulse an athlete can generate it can allow a greater mass to be moved in the same time parameters.
Further adding to the body of literature that strength is needed to be successful in weightlifting, this study demonstrated near perfect correlations between front and back squat and weightlifting performance. While not surprising this study also shows that the athletes need to be powerful alongside the maximal strength which is in alignment with all previous research. These athletes all fall into the elite category which demonstrates that at the top-level strength and power are necessary for high-level performance. Coaches should consider developing maximal strength to agreeable levels while still preserving physical capabilities associated with speed and power which could be accomplished through exercise selection, the inclusion of plyometrics where necessary, and the management of fatigue near the tapering and peaking phases. Additionally, if possible, tracking additional metrics of jumping abilities outside of jump height and peak power may provide further information on what physical qualities to develop in weightlifters.
Practical Applications
Having additional metrics such as propulsive net impulse may serve as additional key performance indicators alongside the traditionally measured aspects of jump height, peak power, and front and back squat maximal strength. While these metrics need to be derived from force plates it provides additional tracking and monitoring of elite weightlifters at the highest level.
References
1. Garhammer, J. (1985). Biomechanical profiles of Olympic weightlifters. Journal of Applied Biomechanics, 1(2), 122-130.
2 . Carlock, J. M., Smith, S. L., Hartman, M. J., Morris, R. T., Ciroslan, D. A., Pierce, K. C., ... & Stone, M. H. (2004). The relationship between vertical jump power estimates and weightlifting ability: a field-test approach. The Journal of Strength & Conditioning Research, 18(3), 534-539.
3. Vizcaya, F. J., Viana, O., del Olmo, M. F., & Acero, R. M. (2009). Could the deep squat jump predict weightlifting performance?. The Journal of Strength & Conditioning Research, 23(3), 729-734.
4. Chavda, S., Lake, J. P., Comfort, P., Bishop, C., Joffe, S. A., & Turner, A. N. (2023). Relationship between kinetic and kinematic measures of the countermovement jump and national weightlifting performance. Journal of Science in Sport and Exercise, 1-13.
5. Joffe, S. A., & Tallent, J. (2020). Neuromuscular predictors of competition performance in advanced international female weightlifters: A cross-sectional and longitudinal analysis. Journal of sports sciences, 38(9), 985-993.
Study: Maximal Isometric Force in the Start of the First Pull Exhibits Greater Correlations with Weightlifting Performance than the Mid-Thigh Pull Position in National and International Weightlifters
What assessments can reveal indicators of performance in competitive weightlifters? Why might different positions reveal greater insights into performance?
Introduction
As discussed in earlier research debriefs, there is good evidence that isometric testing is related to both maximal strength exercises and weightlifting performance (1). However, this is typically done by placing an immovable object in the second pull position -the most powerful position- and pulling as hard as possible for 3-5 seconds. This has provided actionable data which can be tracked over time alongside normal training and reveal if force-time characteristics are improving over time. This test is minimally fatiguing and is reliable to use with this population of athletes.
While the second pull is important for weightlifting success, other positions are critical for a good lift. The start of the lift termed the first pull is the longest phase and dominated by force production necessary to get the bar moving off the floor. The second pull is shorter, and more power dominated as the lift progresses out of the transition because the athlete has more time to impart force into the barbell. The first pull is critical to the lift because it places the athlete in the correct position before the transition to stay balanced and impart force in the right direction into the floor. For this reason, the authors conducted this study to look at the force-time characteristics of both the start position and the second pull and examine its relationship to weightlifting performance.
Purpose
To examine the force characteristics of the first and second pull in high level weightlifters. Correlations to performance will be completed and compared between positions and across athletes.
Methods
Subjects
20 national to international weightlifters (7 men and 13 women) participated in the study. Subjects were well trained and best totals were recorded when they were peaked from competition.
Procedures
Subjects completed two different isometric pull protocols. The first was done in the typical mid-thigh pull position which places the knee angle between 125-145° and the hip between 140-150°. See picture below for set up.
Next subjects completed a pull in the start position of the lift. The standardized position placed the bar 22.5 cm from the floor which is where the bar rests when loaded with plates. Joint angles varied based on the build of the athlete but they ensured that hips were higher than knees and shoulders were higher than hips but allowed for their natural start position. See picture below for set up.
Subjects stood on force plates and were given the cue to “pull as hard and fast as possible” and to keep pulling until they were told to stop. In general, these tests take about 3-5 seconds depending on the athlete. The average of three trials were used for each condition. Best lifts were recorded at either the national championships or international IWF events.
Results
Comparing Positions
More force was produced in the second pull than the start position (2640 N vs 1443 N) which was true for absolute and scaled performance. When examining these positions as it relates to performance very large to nearly perfect correlations were found for the start position and large to nearly perfect were found for the second pull. However, further analysis revealed greater correlations with the start position and performance compared to the second pull.
Discussion
While the second pull of the lifts gets more attention due to its high-power outputs and correlations to performance coaches should not ignore the first pull. Specifically, coaches should examine and develop the force generating capabilities of athletes in the first pull as well as instruct proper execution for an ideal barbell trajectory. The main take away from this study was the isometric start position had a greater relationship to performance compared to the second pull in this group of athletes. This highlights the need for force production in the first pull and how it may relate to performance.
Earlier studies by Beckham et al. and other have show strong correlations between the mid-thigh pull and weightlifting performance (2). This is unsurprising due to the biomechanical similarity between the isometric and the position athletes move through during the dynamic movement. The novelty found in this study is the inclusion of the isometric in the start position. While body positions may vary for athletes, the barbell will always be in the same positions because of the standardized height of the plates with the barbell. This allows for a consistent and replicable test for tracking weightlifters over time. Though total force numbers were lower for the first pull they correlated better with performance compared to the second pull.
The first pull has been considered a more force dominate phase as this is the time the lifter must overcome inertia and start accelerating the barbell. When considering the time of the snatch or clean this phase is the longest. Another consideration is the direction of the force being produced at this time. The direction must be optimal to keep the bar close to the body, limit horizontal movement, and place the barbell in the correct area to execute the transition phase. If force deficits are present during this phase, it could alter the technical execution and place the barbell in the incorrect position which will impact all subsequent phases. The second pull exhibits greater force, velocity, and power due to the time allowed to accelerate the barbell and generate momentum in the movement. This phase is the outcome of all the preceding phases and if executed properly displaces the barbell to the correct height to be caught by the athlete. An important note from the authors was that each phase may be telling you different information about the capabilities of the athlete and therefore, when applicable, both tests should be used to monitor performance.
Practical applications
Don’t ignore the first pull. Producing enough force, in the right direction, with a proper barbell trajectory is critical for later stages of the lift. First, coaches should examine force production in this phase and make sure athletes are strong enough in these positions, then coaches can use exercises to remediate these weaknesses if necessary. Exercises such as heavy lift offs or pulls from a deficit position could rectify these deficiencies. This serves as another monitoring tool which can be incorporated with well-trained athletes to monitor performance.
References
1. Joffe, S. A., Price, P., Chavda, S., Shaw, J., & Tallent, J. (2023). The relationship of lower-body, multijoint, isometric and dynamic neuromuscular assessment variables with snatch, and clean and jerk performance in competitive weightlifters: A meta-analysis. Strength & Conditioning Journal, 45(4), 411-428.
2. Beckham, G., Mizuguchi, S., Carter, C., Sato, K., Ramsey, M., Lamont, H., ... & Stone, M. (2013). Relationships of isometric mid-thigh pull variables to weightlifting performance. J Sports Med Phys Fitness, 53(5), 573-581.
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