PhD S.V. Nopin¹
Dr. Biol., Professor Y.V. Koryagina¹
PhD G.N. Ter-Akopov¹
S.M. Abutalimova¹

¹Federal Scientific and Clinical Center for Specialized Types of Medical Aid and Medical Technologies, FMBA of Russia (FSBISKFNKTSFMBA of Russia, Essentuki

Corresponding author: koru@yandex.ru

Keywords: biomechanics, sports technique, video analysis, tenso-dynamometry, kinematics, weightlifters, clean-and-jerk, gender specifics.

Abstract

Objective of the study was to analyze the gender-specific biomechanics of the modern weightlifting clean-and-jerk techniques.

Methods and structure of the study. The study was timed to the altitude trainings of the Yug Sport Club at the Biomedical Technologies Center of the Federal Scientific and Clinical Center for Specialized Types of Medical Aid and Medical Technologies in Kislovodsk on the 1240m high Small Saddle Mountain. We sampled for the study 45 elite weightlifters of the both sexes qualified Masters of Sport and competing for the Russian national weightlifting team.

We used the BTS Motion System (made by BTS Bioengineering, Italy) described in our prior study using special weightlifting biomechanics processing and analyzing certified software (certificate RU 2020660143, 28.08.2020), with the snatch phase structure analyzed as provided by L.S. Dvorkin. Given on Figure 1 hereunder is a sample of the gender-specific squat phase 7 biomechanics analyzing snapshot.

Results and conclusion. The tests and analyses of the gender-specific clean-and-jerk biomechanics found a statistically significant leadership of the men’s group in the strength, speed, power and weight response speed tests. The women’s group was tested as high as the men’s group in a few kinematic tests including the joint amplitude variation, horizontal weight movement tests and in some clean-and-jerk phases; with notably higher knee/ ankle joint flexion speeds and amplitudes. Based on the study data and analyses, we developed exemplary/ model gender-specific clean-and-jerk biomechanics with the clean-and-jerk technique control and correction recommendations. Some athletes in the sample were recommended to give special attention to the squat/ drop/ stand-up phase timings; dynamic emphases in the drop phase; and the weight control action speeds to improve the individual techniques.

Background. Modern sports techniques on the whole and weightlifting ones in particular are highly efficient and ergonomic i.e. customized to the musculoskeletal system and its capacity. Since the individual anthropometric characteristics, strength and speed-strength capacities are known to be expressly gender-specific, we assumed it could be beneficial to analyze the modern weightlifting techniques in gender groups.

Objective of the study was to analyze the gender-specific biomechanics of the modern weightlifting clean-and-jerk techniques.

Methods and structure of the study. The study was timed to the altitude trainings of the Yug Sport Club at the Biomedical Technologies Center of the Federal Scientific and Clinical Center for Specialized Types of Medical Aid and Medical Technologies in Kislovodsk on the 1240m high Small Saddle Mountain. We sampled for the study 45 elite weightlifters of the both sexes qualified Masters of Sport and competing for the Russian national weightlifting team.

We used the BTS Motion System (made by BTS Bioengineering, Italy) described in our prior study [1] using special weightlifting biomechanics processing and analyzing certified software (certificate RU 2020660143, 28.08.2020) [2], with the snatch phase structure analyzed as provided by L.S. Dvorkin [3]. Given on Figure 1 hereunder is a sample of the gender-specific squat phase 7 biomechanics analyzing snapshot.

Figure 1. Gender-specific squat phase 7 biomechanics analysis

Results and discussion. Subject to the gender-specific clean-and-jerk biomechanics analysis were the timing, strength and speed test rates with the movement range, kinematics and power parameters. The analysis found no statistically significant gender differences in the clean-and-jerk phase times. The strength test rates were unsurprisingly higher in the men’s group including the vertical bipodalic strength component fixed by the force plate in the transitional point of the clean-and-jerk sequence, with the vertical bipodalic strength component maximums and averages fixed and analyzed: see Table hereunder.

Table: Vertical bipodalic strength component maximums and averages in the gender groups, kg

Note: Mann-Whitney U- test

The men’s group was tested with the higher maximum speed test rates in the vertical bipodalic strength component sequence in every phase save for the stand-up one. Statistically significant intergroup differences were found in pull 1.1 (men 800.5 ± 281.8 kg/ s, women 485.3 ± 241.9 kg/ s; p <0.001), pull 1.2 (men 370.7 ± 237.1 kg/ s, women 183.0 ± 110.1 kg/ s; p <0.02), drop 2.2 (men 1138.8 ± 861.1 kg/ s, women 596.1 ± 372.1 kg/ s; p <0.03) and squat 3.1 (men 7615.9 ± 3046.9 kg/ s, women 5476.9 ± 2438.7 kg/ s; p <0.04) phases.

The average lift height was higher in the men group in virtually every clean-and-jerk phase. The right hip joint angle in the transitional point was statistically significantly higher in the women’s group at the end of the drop phase (men 170.3 ± 9.14°; women 179.2 ± 10.14°; p <0.02); as well as the hip joint flexion amplitude in squat 3.2 (men -35.97 ± 15.12°; women -50.91 ± 8.72°; p <0.002), sub-squat 6.1 (men -18.73 ± 7, 54°; women -27.39 ± 10.79°; p <0.03), and sub-squat 6.2 (men 21.21 ± 11.56°; women 31.38 ± 12.56°; p <0.02) phases.

The hip joint angular flexion speed maximums were also different for the gender groups, with the men tested higher at the startup of the drop phase (men 409.2 ± 352.2° / s; women 401.2 ± 87.56° / s; p <0, 03), and women higher at the end of the drop (men 404.8 ± 151.1°/ s; women 508.2 ± 179.6°/ s; p <0.01), squat 3.2 (men 316.3 ± 110.7°/ s; women 454.6 ± 175.3°/ s; p <0.03), stand-up (men 196.7 ± 47.16°/ s; women 266.1 ± 94.82°/ s; p <0.03) and sub-squat 6.1 (men 98.17 ± 14.54°/ s; women 127.8 ± 25.96°/ s; p <0.0004) phases. We also found the knee joint angle intergroup differences at the end of the drop phase (men 166.2 ± 8.87°; women 174.3 ± 9.20°; p <0.01) and in the stand-up phase (men 169.1 ± 11.70°; women 181.2 ± 3.58°; p <0.01) where it was higher in the women group; whilst in the sub-squat and squat-under phases it was higher in the men group. The knee joint angular flexion speed maximum and amplitudes were tested higher in the women group in every clean-and-jerk phase: see Figure 2.

Figure 2. Gender group knee joint angular flexion speed maximum and amplitude averages, °/s (pull 1.1, pull 1.2, drop 2.1, drop 2.2, squat 3.1, squat 3.2, stand-up 4, sub-squat 6.1, sub-squat 6.2, squat-under 7; and stand-up 7 and 8 phases)

The right ankle joint angles were higher in the men group in pull 1.1, drop 2.1, squat 3.2 and stand-up 8 phases. The women group showed higher ankle joint flexion amplitudes in drop phase 2.2. The men’s group showed higher ankle joint flexion amplitude in pull 1.1 phase and stand-up phase; and the women’s group was tested higher on this scale in drop 2.1, drop 2.2 and squat 3.2 phases.

The men group was also tested meaningfully higher in the vertical effective power maximum versus body weight (W/kg) test in every phase: see Figure 3.

Figure 3. Gender group averages in the vertical effective power maximum versus body weight (W/kg) test: (pull 1.1, pull 1.2, drop 2.1, drop 2.2, squat 3.1, squat 3.2, stand-up 4, sub-squat 6.1, sub-squat 6.2, squat-under 7; and stand-up 7 and 8)

Conclusion. The tests and analyses of the gender-specific clean-and-jerk biomechanics found a statistically significant leadership of the men’s group in the strength, speed, power and weight response speed tests. The women’s group was tested as high as the men’s group in a few kinematic tests including the joint amplitude variation, horizontal weight movement tests and in some clean-and-jerk phases; with notably higher knee/ ankle joint flexion speeds and amplitudes. Based on the study data and analyses, we developed exemplary/ model gender-specific clean-and-jerk biomechanics with the clean-and-jerk technique control and correction recommendations. Some athletes in the sample were recommended to give special attention to the squat/ drop/ stand-up phase timings; dynamic emphases in the drop phase; and the weight control action speeds to improve the individual techniques.

The study was performed under Governmental Contract #0173100014420000023 of 15.06.2020 endorsed by the national Ministry of Sports

References

1. Nopin S.V., Koryagina J.V., Ter-Akopov G.N. Functional status of locomotor system of athletes engaged in cyclic and situational sports. Teoriya i praktika fiz. kultury. 2020. No. 4. pp. 25-27.
2. Nopin S.V. Biomechanical and electromyographic rapid assessment of weightlifting jerk. Certificate of registration of the computer program RU 2020660143, 28.08.2020. Appl. # 2020619201/69 dated 20.08.2020.
3. Dvorkin L.S., Slobodyan A.P. Weightlifting. Textbook for universities; vol. 1, 2. Moscow: Sovetskiy sport publ., 2005. 600 p.