scholarly journals Peculiarities of Muscle-Tendon Mechanics and Energetics in Elite Athletes in Various Sports

2021 ◽  
Author(s):  
Mikhail Shestakov ◽  
Anna Zubkova
Keyword(s):  
Elite Athletes ◽  
Motor Task ◽  
Elastic Strain Energy ◽  
Metabolic Energy ◽  
Arm Swing ◽  
Energy Expenditures ◽  
Tendon Mechanics ◽  
Drop Jumps ◽  
Muscle Groups ◽  
Training Exercises

The article presents results of the research on jumping strategies applied by elite athletes in various sport disciplines. Research hypothesis: to perform the same motor task athletes employ different ways of organizing the movement and different features of MTU functioning. The choice of a mechanism to enhance muscle contraction depends on sport discipline, in particular specific features of the sport movement. The study involved members of the Russian national teams in alpine skiing, bobsleighing, mogul skiing and ski jumping. The athletes performed drop jumps from the heights of 0.1, 0.3, and 0.5 m with no arm swing. Experimental data were obtained online from 24 cameras using the Qualisys motion capture system (400 frames per second) and the two force plates AMTI 6000. Data was processed using the OpenSim package. The authors calculated the amount of accumulation and utilization of elastic strain energy and assessed metabolic energy expenditures in MTU. The authors concluded that employment of different strategies of movement organization in drop jumps could be explained by the transfer of motor skills specific to the athlete’s sport discipline. The results of the study may help coaches develop individual training plans for athletes, in particular strength training exercises targeting specific muscle groups.

scholarly journals Using a simple rope-pulley system that mechanically couples the arms, legs, and treadmill reduces the metabolic cost of walking

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Daisey Vega ◽  
Christopher J. Arellano
Keyword(s):  
Metabolic Cost ◽  
Metabolic Energy ◽  
Metabolic Effects ◽  
Whole Body ◽  
Walking Ability ◽  
Arm Swing ◽  
Pulley System ◽  
Young Subjects ◽  
Walking Recovery ◽  
Set Up

Abstract Background Emphasizing the active use of the arms and coordinating them with the stepping motion of the legs may promote walking recovery in patients with impaired lower limb function. Yet, most approaches use seated devices to allow coupled arm and leg movements. To provide an option during treadmill walking, we designed a rope-pulley system that physically links the arms and legs. This arm-leg pulley system was grounded to the floor and made of commercially available slotted square tubing, solid strut channels, and low-friction pulleys that allowed us to use a rope to connect the subject’s wrist to the ipsilateral foot. This set-up was based on our idea that during walking the arm could generate an assistive force during arm swing retraction and, therefore, aid in leg swing. Methods To test this idea, we compared the mechanical, muscular, and metabolic effects between normal walking and walking with the arm-leg pulley system. We measured rope and ground reaction forces, electromyographic signals of key arm and leg muscles, and rates of metabolic energy consumption while healthy, young subjects walked at 1.25 m/s on a dual-belt instrumented treadmill (n = 8). Results With our arm-leg pulley system, we found that an assistive force could be generated, reaching peak values of 7% body weight on average. Contrary to our expectation, the force mainly coincided with the propulsive phase of walking and not leg swing. Our findings suggest that subjects actively used their arms to harness the energy from the moving treadmill belt, which helped to propel the whole body via the arm-leg rope linkage. This effectively decreased the muscular and mechanical demands placed on the legs, reducing the propulsive impulse by 43% (p < 0.001), which led to a 17% net reduction in the metabolic power required for walking (p = 0.001). Conclusions These findings provide the biomechanical and energetic basis for how we might reimagine the use of the arms in gait rehabilitation, opening the opportunity to explore if such a method could help patients regain their walking ability. Trial registration: Study registered on 09/29/2018 in ClinicalTrials.gov (ID—NCT03689647).

scholarly journals How Much Energy Vaquejada Horses Spend in a Field Simulation Test?

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3421
Author(s):  
Clarisse S. Coelho ◽  
Ticiane D. R. P. Sodre ◽  
Lara N. Sousa ◽  
Renata F. Siqueira ◽  
Helio C. Manso Filho ◽  
...  
Keyword(s):  
Well Being ◽  
Metabolic Energy ◽  
Energy Requirements ◽  
Transport Costs ◽  
Simulation Test ◽  
Blood Samples ◽  
Energy Expenditures ◽  
Field Simulation ◽  
Set Up ◽  
One Way Anova

Vaquejada is a high-intensity and short-duration exercise in which helper horses (HH) are responsible to keep a bull running in a line while pull horses (PH) work to put the bull down after 100 m of running. The purpose of this study was to quantify and compare energy expenditures (EE), transport costs (COT) and metabolic energy requirements (Pmet) of horses used in Vaquejada. Thus, eight Quarter Horses, in randomly formed pairs, performed a vaquejada simulation test (VST), which consisted of three races on a sand track (130–150 m), with a 5-min interval between them. All horses used an integrated heart rate (HR) and GPS monitoring system (V800, Polar Electro) and, from these data, EE, COT and Pmet were calculated using the formulas: EE (J/kg/min) = 0.0566 × HR1.9955, COT = (HR-35)/kg/m × 103 and Pmet = (HR-35)/min/kg. Blood samples were collected for lactate analysis at rest, immediately after the first, second and third race and after 30 min of recovery. Data obtained were submitted to one-way ANOVA and Tukey tests (p ≤ 0.05). In VST, HH had higher EE and higher HR at trot; while PH presented higher EE and HR at canter. Finally, considering total VST, PH had higher EE and COT, while HH had higher Pmet. Lactate was higher in PH. Despite practicing the same sport, PH and HH should be considered distinct athletes, and these must be considered to set up appropriate physical and nutritional programs, which will lead to better performance and guarantees of well-being.

scholarly journals Efecto agudo del orden de ejecución de ejercicios contra resistencia sobre la presión arterial en jóvenes estudiantes normotensos (Acute effect of the order of execution of resistance exercises on blood pressure in normotensive young students)

Retos ◽  
2016 ◽  
pp. 68-71
Author(s):  
Engell Quesada Valle ◽  
Andrea Solera Herrera
Keyword(s):  
Blood Pressure ◽  
Resistance Training ◽  
Hypotensive Effect ◽  
Acute Effect ◽  
Control Group ◽  
Experimental Conditions ◽  
Exercise Blood Pressure ◽  
Young Students ◽  
Muscle Groups ◽  
Training Exercises

Objetivo: El objetivo de la presente investigación fue determinar el efecto del orden de ejecución de ejercicios contra resistencia (CR) sobre la presión arterial (PA) en reposo de jóvenes estudiantes normotensos. Método: Para el estudio se contó con la participación de 14 hombres sanos, familiarizados con el ejercicio de contra resistencia con edad promedio de 23.3 ± 1.4 años. Las condiciones experimentales fueron realizadas en orden aleatorizado, en diferentes días de trabajo y consistieron en: (1) iniciar el ejercicio CR con grupo muscular grande y terminar con pequeños (G-Peq), (2) iniciar con grupos musculares pequeño y finalizar con grandes (P-Gde) y (3), condición control .La rutina de ejercicio constó de ocho ejercicios  los cuales se trabajaron al 60% de 1 repetición máxima (RM), se realizaron 3 series de 10 repeticiones para cada ejercicio , las mediciones de presiones arteriales se tomaron antes del ejercicio, al terminar el  ejercicio y cada 10 minutos luego de terminar la rutina durante 1 hora. Resultados: En la PA sistólica se encontraron disminuciones importantes durante 30 min tanto de la condición G-Peq como de la P-Gde en comparación con el grupo control (p≤ 0.001), no obstante, la magnitud de la disminución fue mayor posterior a G-Peq (6-11 mm Hg) en comparación con P-Gde (4-10 mm Hg). Para la PA diastólica no se encontró interacción significativa (p=0.39). Conclusión. Existe efecto hipotensor posterior a ambas rutinas, sin embargo, se observó una disminución mayor de la PA sistólica al finalizar la rutina con grupos musculares grandes. Abstract. Objective: The aim of this study was to determine the effect of the order of execution of resistance training exercises (RT) on blood pressure (BP) in normotensive young students at rest. Method: 14 healthy men (mean age of 23.3 ± 1.4 years) who were familiar with resistance training participated in this study. The order of participation for the experimental conditions was randomized; the different conditions consisted in: (1) RT starting with large muscles groups and finishing with small ones (L-S), (2) RT starting with small muscles groups and ending with large ones (S-L) and (3) the control condition. RT routine consisted of eight exercises with intensity of 60% of one repetition maximum (RM). The participants performed 3 sets of 10 repetitions for each exercise. Blood pressure measurements were taken before exercise, at the end of the year, and every 10 minutes after finishing the routine for 1 hour. Results: systolic BP reduction was found for 30 min both in L-S and S-L compared with the control group (p ≤ 0.001), although the magnitude of the decrease was higher after L-S (6-11 mmHg) compared with S-L (4-10 mmHg). For diastolic BP no significant interaction was found (p=0.39). Conclusion There exists a hypotensive effect after both routines; however, there was a greater decrease of systolic BP at the end of the routine with large muscle groups.

Resistance training exercise selection: efficiency, safety and comfort analysis method

2021 ◽  
Vol 23 ◽  
Author(s):  
Ewertton de Souza Bezerra ◽  
Brad J. Schoenfeld ◽  
Lucas Bet da Rosa Orssatto ◽  
Jerry L. Mayhew ◽  
Alex Silva Ribeiro
Keyword(s):  
Resistance Training ◽  
Substantial Effect ◽  
Analysis Method ◽  
Resistance Training Exercise ◽  
Muscle Adaptations ◽  
Major Variable ◽  
Muscle Groups ◽  
Safety Considerations ◽  
Training Exercises ◽  
Safety Procedures

Abstract Manipulation of resistance training variables has been shown to have a substantial effect on muscular adaptations. A major variable in this process is exercise selection. In addition to the effectiveness of a given exercise to recruit the target muscle groups, safety considerations and individual comfort during execution of a lift should be considered. The correct biomechanics of the chosen exercise will assist in promoting desired muscle adaptations, while proper safety procedures will reduce risk of injury. Lifting comfort will facilitate enjoyment and foster adherence to the program. Therefore, the purpose of this paper was to offer guidelines for selection of resistance training exercises based on the Efficiency, Safety, and Comfort Analysis Method (ESCAM).

The Quiet Eye durations of air pistol shooting athletes

2021 ◽  
Vol 15 (7) ◽  
pp. 2246-2252
Author(s):  
Tonguç Vardar ◽  
Fatih Senduran
Keyword(s):  
Eye Tracking ◽  
Elite Athletes ◽  
Critical Role ◽  
Computer Software ◽  
Motor Task ◽  
Biometric Analysis ◽  
Quiet Eye ◽  
Preparation Period ◽  
Recorded Data ◽  
Tracking Device

Background: The Focusing the attention during the preparation period undergone immediately before carrying out a motor performance is vitally important for success. Visual ability, Quiet Eye and focusing the attention on the appropriate area play a critical role in achieving successful performance in branches of sport. Quiet eye (QE) is defined as the final fixation of the pupil on a location or object for a specific motor task. Aim: The aim of this study was to examine the durations of effective and final focusing (quiet eye) carried out during the process of taking aim at the target by air pistol shooting athletes with their eyes immediately before taking a shot. Methods: A total of 8 right-handed male licensed pistol shooting athletes (4 novice and 4 elite) participated in the research. A total of 320 shots -160 dry (unscored) and 160 live (scored) shots were taken by the novice and elite athletes. For the purpose of recording pupil movements and quiet eye durations during the shots taken by the athletes, an eye-tracking device attached to the head was used. The recorded data were examined with iMotions computer software, which can perform biometric analysis. The athletes’ quiet eye durations occurring when taking aim at the target were examined according to athletes’ characteristics (novice and elite) and the type of shot carried out (scored and unscored) by means of the independent samples t-test. Results: The findings of the study revealed that the athletes had 25.3% longer quiet eye durations when firing scored shots than when firing unscored shots (p = .000). Especially, novice athletes exhibited 37.8% longer periods of focusing behaviour when firing scored shots than when firing unscored shots (p = .000). Elite athletes displayed 21.26% longer periods of focusing behaviour when firing unscored shots compared with novice athletes (p = .005). Conclusion: According to the results of the research, it can be said that in the sport of air pistol shooting, giving priority to dry shooting training and conducting special exercises for developing quiet eye (QE) duration can contribute positively to the development of novice athletes’ shooting skills. Keywords: Quiet eye, eye tracking, air pistol, shooting, motor skill, cognitive processes

The work and energetic cost of locomotion. II. Partitioning the cost of internal and external work within a species

1990 ◽  
Vol 154 (1) ◽  
pp. 287-303 ◽  
Author(s):  
K. Steudel
Keyword(s):  
Center Of Mass ◽  
Elastic Strain Energy ◽  
Mechanical Work ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
External Work ◽  
Internal Work ◽  
Cost Of Locomotion ◽  
Large Animals ◽  
The Cost

Previous studies have shown that large animals have systematically lower mass-specific costs of locomotion than do smaller animals, in spite of there being no demonstrable difference between them in the mass-specific mechanical work of locomotion. Larger animals are somehow much more efficient at converting metabolic energy to mechanical work. The present study analyzes how this decoupling of work and cost might occur. The experimental design employs limb-loaded and back-loaded dogs and allows the energetic cost of locomotion to be partitioned between that used to move the center of mass (external work) and that used to move the limbs relative to the center of mass (internal work). These costs were measured in three dogs moving at four speeds. Increases in the cost of external work with speed parallel increases in the amount of external work based on data from previous studies. However, increases in the cost of internal work with speed are much less (less than 50%) than the increase in internal work itself over the speeds examined. Furthermore, the cost of internal work increases linearly with speed, whereas internal work itself increases as a power function of speed. It is suggested that this decoupling results from an increase with speed in the extent to which the internal work of locomotion is powered by non-metabolic means, such as elastic strain energy and transfer of energy within and between body segments.

scholarly journals The influence of Achilles tendon mechanical behaviour on “apparent” efficiency during running at different speeds

2020 ◽  
Vol 120 (11) ◽  
pp. 2495-2505 ◽  
Author(s):  
Andrea Monte ◽  
Constantinos Maganaris ◽  
Vasilios Baltzopoulos ◽  
Paola Zamparo
Keyword(s):  
Achilles Tendon ◽  
Mechanical Behaviour ◽  
Elastic Strain Energy ◽  
Metabolic Energy ◽  
Net Energy ◽  
Metabolic Demand ◽  
Running Speed ◽  
Dynamic Function ◽  
Positive Correlations

Abstract Purpose We investigated the role of elastic strain energy on the “apparent” efficiency of locomotion (AE), a parameter that is known to increase as a function of running speed (up to 0.5–0.7) well above the values of “pure” muscle efficiency (about 0.25–0.30). Methods In vivo ultrasound measurements of the gastrocnemius medialis (GM) muscle–tendon unit (MTU) were combined with kinematic, kinetic and metabolic measurements to investigate the possible influence of the Achilles tendon mechanical behaviour on the mechanics (total mechanical work, WTOT) and energetics (net energy cost, Cnet) of running at different speeds (10, 13 and 16 km h−1); AE was calculated as WTOT/Cnet. Results GM fascicles shortened during the entire stance phase, the more so the higher the speed, but the majority of the MTU displacement was accommodated by the Achilles tendon. Tendon strain and recoil increased as a function of running speed (P < 0.01 and P < 0.001, respectively). The contribution of elastic energy to the positive work generated by the MTU also increased with speed (from 0.09 to 0.16 J kg−1 m−1). Significant negative correlations (P < 0.01) were observed between tendon work and metabolic energy at each running speed (the higher the tendon work the lower the metabolic demand) and significant positive correlations were observed between tendon work and AE (P < 0.001) at each running speed (the higher the tendon work the higher the efficiency). Conclusion These results support the notion that the dynamic function of tendons is integral in reducing energy expenditure and increasing the “apparent” efficiency of running.

scholarly journals Control at stability's edge minimizes energetic costs: expert stick balancing

2016 ◽  
Vol 13 (119) ◽  
pp. 20160212 ◽  
Author(s):  
John Milton ◽  
Ryan Meyer ◽  
Max Zhvanetsky ◽  
Sarah Ridge ◽  
Tamás Insperger
Keyword(s):  
Time Delay ◽  
Balance Control ◽  
Dead Zone ◽  
Minimum Energy ◽  
Motor Task ◽  
Vertical Displacement ◽  
Energy Expenditures ◽  
Switching Type ◽  
Displacement Angle ◽  
The Cost

Stick balancing on the fingertip is a complex voluntary motor task that requires the stabilization of an unstable system. For seated expert stick balancers, the time delay is 0.23 s, the shortest stick that can be balanced for 240 s is 0.32 m and there is a ° dead zone for the estimation of the vertical displacement angle in the saggital plane. These observations motivate a switching-type, pendulum–cart model for balance control which uses an internal model to compensate for the time delay by predicting the sensory consequences of the stick's movements. Numerical simulations using the semi-discretization method suggest that the feedback gains are tuned near the edge of stability. For these choices of the feedback gains, the cost function which takes into account the position of the fingertip and the corrective forces is minimized. Thus, expert stick balancers optimize control with a combination of quick manoeuvrability and minimum energy expenditures.

Which Muscles Power the Human Running Stride?

2012 ◽  
Author(s):  
Tim W. Dorn ◽  
Yi-Chung Lin ◽  
Anthony G. Schache ◽  
Marcus G. Pandy
Keyword(s):  
Muscle Power ◽  
Center Of Mass ◽  
The Body ◽  
Metabolic Energy ◽  
Running Speed ◽  
Limb Coordination ◽  
External Power ◽  
Muscle Groups ◽  
The Individual ◽  
Human Running

Running is a physically demanding activity that requires explosive delivery of muscle power to the ground during stance, and precise, yet rapid limb coordination during swing. In particular, as running speed increases, greater metabolic energy in the form of muscle mechanical work is required to power the motion of: i) the center-of-mass (i.e., external power); and ii) the individual limb segments (i.e., internal power) [1,2]. The purpose of this study was to quantify the contributions that individual muscles make to the external and internal power of the body across a range of running speeds so as to identify the key muscle groups in coordinating a full running stride.

Guidelines for Sport Coaches on Core-Strengthening Techniques for Athletes: Improving Performance and Decreasing the Occurrence of Lower Back Pain

2013 ◽  
Vol 6 (2) ◽  
pp. 135-147
Author(s):  
Micailah Brock ◽  
Sheri Huckleberry
Keyword(s):  
Back Pain ◽  
Lower Back Pain ◽  
Musculoskeletal Injury ◽  
Trunk Flexion ◽  
Lower Back ◽  
Training Specificity ◽  
Athletic Activities ◽  
Muscle Groups ◽  
Training Exercises ◽  
Sport Coaches

This paper introduces the concept of dynamic isometrics in training athletes to improve core/postural-related movements while potentially decreasing the occurrence of injury manifested as lower back pain (LBP). Moreover, suggested resistance-training exercises are provided to guide the sport coach. Lower back pain is a common musculoskeletal injury that can be caused by imbalances between anterior and posterior muscle groups. Traditional exercises such as sit-ups and crunches are insufficient as preventatives because very few athletic movements are performed with weighted trunk flexion. Alternatively, sport coaches could implement dynamic isometric training, which closely reflects athletic activities, supports the principle of training specificity, improves balance and strength, and might decrease the occurrence of LBP (Hamlyn, Behm, & Young, 2007).

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