scholarly journals Biomechanical characteristics of Taekwondo athletes: kicks and punches vs. laboratory tests

2018 ◽  
Vol 10 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Krzysztof Buśko ◽  
Pantelis T. Nikolaidis
Keyword(s):  
Muscle Strength ◽  
Power Output ◽  
Laboratory Tests ◽  
Jump Height ◽  
Joint Torques ◽  
Maximal Force ◽  
Counter Movement Jump ◽  
Force Velocity ◽  
Muscle Groups ◽  
Strong Relationships

Summary Study aim: The aim of the study was to examine biomechanical characteristics of taekwondo athletes comparing kicks and punches with laboratory tests of muscle strength and power. Material and methods: Six male taekwondo athletes participated in this study. Measurements of maximal punching with the rear hand (hook and straight punches) and kicking (Apdolio and Dwit Chagi) force were performed on a boxing dynamometer. Also, the following laboratory tests were performed: jump height and power output in counter movement jump (CMJ) and spike jump (SPJ), muscle strength for 10 muscle groups and force-velocity (F-v) relationship. Results: Mean maximal straight and hook punching forces were 1659.2 ± 254.2 N and 1843.8 ± 453.3 N, respectively. Maxi­mal Apdolio rear leg, Apdolio lead leg and Dwit Chagi rear leg kicking forces were 3541.3 ± 1130.3 N, 3205.3 ± 965.1 N and 3568.0 ± 1306.0 N, respectively. The heights of jumps were 0.501 ± 0.040 m (CMJ) and 0.554 ± 0.034 m (SPJ). A strong cor­relation between the maximal force of a punch and maximal joint torques was observed. Conclusions: The values of kicking forces developed in a simulated fight were lower than the forces developed in the test of individual kicks. Strong relationships were observed between leg power developed in the SPJ and force of individual Apdolio kicks performed with the lead (r = 0.87, p < 0.05) and rear leg (r = 0.74). Based on these findings, it was concluded that maxi­mal joint torques and height of the SPJ could be used as a proxy of kicking force.

Lower Limb Force, Velocity, Power Capabilities during Leg Press and Squat Movements

2017 ◽  
Vol 38 (14) ◽  
pp. 1083-1089 ◽  
Author(s):  
Johnny Padulo ◽  
Gian Migliaccio ◽  
Luca Ardigò ◽  
Bruno Leban ◽  
Marco Cosso ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Effect Size ◽  
Power Output ◽  
Lower Limb ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Optimal Velocity ◽  
Leg Press ◽  
Maximal Force ◽  
Force Velocity

AbstractThe aim was to compare lower-limb power, force, and velocity capabilities between squat and leg press movements. Ten healthy sportsmen performed ballistic lower-limb push-offs against 5-to-12 different loads during both the squat and leg press. Individual linear force-velocity and polynomial power-velocity relationships were determined for both movements from push-off mean force and velocity measured continuously with a pressure sensor and linear encoder. Maximal power output, theoretical maximal force and velocity, force-velocity profile and optimal velocity were computed. During the squat, maximal power output (17.7±3.59 vs. 10.9±1.39 W·kg−1), theoretical maximal velocity (1.66±0.29 vs. 0.88±0.18 m·s−1), optimal velocity (0.839±0.144 vs. 0.465±0.107 m·s−1), and force-velocity profile (−27.2±8.5 vs. −64.3±29.5 N·s·m−1·kg−1) values were significantly higher than during the leg press (p=0.000, effect size=1.72–3.23), whereas theoretical maximal force values (43.1±8.6 vs. 51.9±14.0 N·kg−1, p=0.034, effect size=0.75) were significantly lower. The mechanical capabilities of the lower-limb extensors were different in the squat compared with the leg press with higher maximal power due to much higher velocity capabilities (e.g. ability to produce force at high velocities) even if moderately lower maximal force qualities.

scholarly journals Jump height is a poor indicator of lower limb maximal power output: theoretical demonstration, experimental evidence and practical solutions

2018 ◽  
Author(s):  
Jean-Benoit Morin ◽  
Pedro Jiménez-Reyes ◽  
Matt Brughelli ◽  
Pierre Samozino
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Lower Limb ◽  
Force Plate ◽  
Computation Method ◽  
Jump Height ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Sports Science ◽  
Force Velocity

Lower limb maximal power output (Pmax) is a key physical component of performance in many sports. During squat jump (SJ) and countermovement jump (CMJ) tests, athletes produce high amounts of mechanical work over a short duration to displace their body mass (i.e. the dimension of mechanical power). Thus, jump height has been frequently used by the sports science and medicine communities as an indicator of Pmax. However, in this article, we contended that SJ and CMJ height are in fact poor indicators of Pmax in trained populations. To support our opinion, we first detailed why, theoretically, jump height and Pmax are not fully related. Specifically, we demonstrated that individual body mass, distance of push-off, optimal loading and force-velocity characteristics confound the jump height-Pmax relationship. We also discussed the poor relationship between SJ or CMJ height and Pmax measured with a force plate based on data reported in the literature, which added to our own experimental evidence.Finally, we discussed the limitations of existing practical solutions (regression-based estimation equations and allometric scaling), and advocated using a valid, reliable and simple field-based procedure to compute individual Pmax directly from jump height, body mass and push-off distance. The latter may allow researchers and practitioners to reduce bias in their assessment of Pmax by using jump height as an input with a simple yet accurate computation method, and not as the first/only variable of interest.

scholarly journals The Influence of the Menstrual Cycle on Muscle Strength and Power Performance

2019 ◽  
Vol 68 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Blanca Romero-Moraleda ◽  
Juan Del Coso ◽  
Jorge Gutiérrez-Hellín ◽  
Carlos Ruiz-Moreno ◽  
Jozo Grgic ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Muscle Strength ◽  
Power Output ◽  
Repeated Measures ◽  
Follicular Phase ◽  
Muscle Performance ◽  
Power Performance ◽  
Repetition Maximum ◽  
Squat Exercise ◽  
Force Velocity

AbstractThis study aimed to investigate the fluctuations of muscle performance in the Smith machine half-squat exercise during three different phases of the menstrual cycle. Thirteen resistance-trained and eumenorrheic women volunteered to participate in the study (58.6 ± 7.8 kg, 31.1 ± 5.5 years). In a pre-experimental test, the half-squat one-repetition maximum (1RM) was measured. Body mass, tympanic temperature and urine concentration of the luteinizing hormone were estimated daily for ~30 days to determine the early follicular phase (EFP), the late follicular phase (LFP), and the mid-luteal phase (MLP) of the menstrual cycle. On the second day of each phase, performance of the Smith machine half-squats was assessed using 20, 40, 60 and 80% of one repetition maximum (1RM). In each load, force, velocity, and power output were measured during the concentric phase of the exercise by means of a rotatory encoder. The data were analyzed using one-way repeated measures ANOVA coupled with magnitude-based inferences. Overall, force, velocity and power output were very similar in all menstrual cycle phases with unclear differences in most of the pairwise comparisons and effect sizes >0.2. The results of this investigation suggest that eumenorrheic females have similar muscle strength and power performance in the Smith machine half-squat exercise during the EFP, LFP, and MLP phases of the menstrual cycle.

scholarly journals Recovery of early postoperative muscle strength after deep neuromuscular block by means of ultrasonography with comparison of neostigmine versus sugammadex as reversal drugs: study protocol for a randomised controlled trial

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043935
Author(s):  
Xuan Wang ◽  
Yingyuan Li ◽  
Chanyan Huang ◽  
Wei Xiong ◽  
Qin Zhou ◽  
...  
Keyword(s):  
Randomised Controlled Trial ◽  
Muscle Strength ◽  
Neuromuscular Blockade ◽  
Postoperative Period ◽  
Controlled Trial ◽  
Complete Recovery ◽  
Early Postoperative Period ◽  
Time Points ◽  
Muscle Groups ◽  
Randomised Controlled

IntroductionDespite the use of quantitative neuromuscular monitoring together with the administration of reversal drugs (neostigmine or sugammadex), the incidence of residual neuromuscular blockade defined as a train-of-four ratio (TOFr) <0.9 remains high. Even TOFr >0.9 cannot ensure adequate recovery of neuromuscular function when T1 height is not recovered completely. Thus, a mathematical correction of TOFr needs to be applied because the return of a normal TOFr can precede the return of a normal T1 twitch height. On the other hand, different muscles have different sensitivities to neuromuscular blockade agents; thus, complete recovery of one specific muscle group does not represent complete recovery of all other muscles. Therefore, our study aims to assess the muscle strength recovery of respiratory-related muscle groups by ultrasound and evaluate global strength using handgrip dynamometry in the early postoperative period when TOFr=0.9 and corrected TOFr (cTOFr)=0.9 with comparison of neostigmine versus sugammadex as reversal drugs.Methods and analysisThis study will be a prospective, single-blinded, randomised controlled trial involving 60 patients with American Society of Anesthesiologists physical status I–II and aged between 18 and 65 years, who will undergo microlaryngeal surgery. We will assess geniohyoid muscle, parasternal intercostal muscle, diaphragm, abdominal wall muscle and handgrip strength at four time points: before anaesthesia, TOFr=0.9, cTOFr=0.9 and 30 min after admission to the post anaesthesia care unit. Our primary objective will be to compare the effects of neostigmine and sugammadex on the recovery of muscle strength of different muscle groups in the early postoperative period when TOFr=0.9 and cTOFr=0.9. The secondary objective will be to observe the difference of muscle strength between the time points of TOFr=0.9 and cTOFr=0.9 to find out the clinical significance of cTOFr >0.9.Ethics and disseminationThe protocol was reviewed and approved by the Ethics Committee of The First Affiliated Hospital, Sun Yat-sen University. The findings will be disseminated to the public through peer-reviewed scientific journals.Trial registration numberChiCTR2000033832.

Fatigue of mouse soleus muscle, using the work loop technique.

1997 ◽  
Vol 200 (22) ◽  
pp. 2907-2912 ◽  
Author(s):  
G N Askew ◽  
I S Young ◽  
J D Altringham
Keyword(s):  
Soleus Muscle ◽  
Power Output ◽  
Cycle Frequency ◽  
Reduction In Force ◽  
Negative Work ◽  
Loop Shape ◽  
Force Velocity ◽  
Positive Work ◽  
Work Loop

The function of many muscles requires that they perform work. Fatigue of mouse soleus muscle was studied in vitro by subjecting it to repeated work loop cycles. Fatigue resulted in a reduction in force, a slowing of relaxation and in changes in the force-velocity properties of the muscle (indicated by changes in work loop shape). These effects interacted to reduce the positive work and to increase the negative work performed by the muscle, producing a decline in net work. Power output was sustained for longer and more cumulative work was performed with decreasing cycle frequency. However, absolute power output was highest at 5 Hz (the cycle frequency for maximum power output) until power fell below 20% of peak power. As cycle frequency increased, slowing of relaxation had greater effects in reducing the positive work and increasing the negative work performed by the muscle, compared with lower cycle frequencies.

Force-velocity and force-power properties of single muscle fibers from elite master runners and sedentary men

1996 ◽  
Vol 271 (2) ◽  
pp. C676-C683 ◽  
Author(s):  
J. J. Widrick ◽  
S. W. Trappe ◽  
D. L. Costill ◽  
R. H. Fitts
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Power Output ◽  
Peak Power ◽  
Isometric Force ◽  
Peak Force ◽  
Peak Power Output ◽  
Type I ◽  
Shortening Velocity ◽  
Force Velocity

Gastrocnemius muscle fiber bundles were obtained by needle biopsy from five middle-aged sedentary men (SED group) and six age-matched endurance-trained master runners (RUN group). A single chemically permeabilized fiber segment was mounted between a force transducer and a position motor, subjected to a series of isotonic contractions at maximal Ca2+ activation (15 degrees C), and subsequently run on a 5% polyacrylamide gel to determine myosin heavy chain composition. The Hill equation was fit to the data obtained for each individual fiber (r2 > or = 0.98). For the SED group, fiber force-velocity parameters varied (P < 0.05) with fiber myosin heavy chain expression as follows: peak force, no differences: peak tension (force/fiber cross-sectional area), type IIx > type IIa > type I; maximal shortening velocity (Vmax, defined as y-intercept of force-velocity relationship), type IIx = type IIa > type I; a/Pzero (where a is a constant with dimensions of force and Pzero is peak isometric force), type IIx > type IIa > type I. Consequently, type IIx fibers produced twice as much peak power as type IIa fibers, whereas type IIa fibers produced about five times more peak power than type I fibers. RUN type I and IIa fibers were smaller in diameter and produced less peak force than SED type I and IIa fibers. The absolute peak power output of RUN type I and IIa fibers was 13 and 27% less, respectively, than peak power of similarly typed SED fibers. However, type I and IIa Vmax and a/Pzero were not different between the SED and RUN groups, and RUN type I and IIa power deficits disappeared after power was normalized for differences in fiber diameter. Thus the reduced absolute peak power output of the type I and IIa fibers from the master runners was a result of the smaller diameter of these fibers and a corresponding reduction in their peak isometric force production. This impairment in absolute peak power production at the single fiber level may be in part responsible for the reduced in vivo power output previously observed for endurance-trained athletes.

scholarly journals Effects of cross-bridge compliance on the force-velocity relationship and muscle power output

PLoS ONE ◽  
2017 ◽  
Vol 12 (12) ◽  
pp. e0190335 ◽  
Author(s):  
Axel J. Fenwick ◽  
Alexander M. Wood ◽  
Bertrand C. W. Tanner
Keyword(s):  
Power Output ◽  
Muscle Power ◽  
Cross Bridge ◽  
Velocity Relationship ◽  
Force Velocity ◽  
Muscle Power Output
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