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David Hawkins and Mark Smeulders

The purpose of this study was to determine if the characteristic Hill model, used to describe me force–velocity relationship for isolated tetanically stimulated muscle, could be modified and used to describe me torque–velocity behavior of me hip for maximally and submaximally stimulated hip extensor muscles. Fourteen subjects performed hip extension movements at effort levels of 100%, 70%, and 40% of a maximum isometric effort. A solenoid provided isometric resistance to hip extension. Once the desired effort level was achieved, as indicated by me isometric force, the solenoid released and me hip moved against an opposing elastic resistance equal to 75%, 50%, 25%, and 0% of the specified effort level. An electrogoniometer quantified hip angle. Hip velocity was determined by numerically differentiating the angle data. Torque-velocity-activation (or effort level) data were determined for each trial. Model parameters were determined to give me best fit to the data for each subject. Average parameter values were determined for each gender and for the entire group. The modified Hill-type model, T m = (T max · AK 1 · ω)/(K2 · ω + 1), accurately describes me relationship between joint torque (T m), maximum isometric joint torque (T max), joint velocity (ω), and muscle activation level (A) for subject-specific parameters (K 1 and K 2), but not for parameters averaged across genders or the entire group. Values for T max, K 1, and K 2 ranged from 90 to 385 Nm, 6.1 to 47.9 Nms, and 0.030 to 0.716 s, respectively.

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Natália Barros Beltrão, Camila Ximenes Santos, Valéria Mayaly Alves de Oliveira, André Luiz Torres Pirauá, David Behm, Ana Carolina Rodarti Pitangui, and Rodrigo Cappato de Araújo

significantly affect changes in range of motion (ROM), 2 , 3 passive torque response, 3 and muscle architecture, 4 there are few studies investigating stretch intensity effects within a chronic flexibility training program. There is conflict regarding stretching intensity in the literature, with some acute

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Karinna Sonálya Aires da Costa, Daniel Tezoni Borges, Liane de Brito Macedo, Caio Alano de Almeida Lins, and Jamilson Simões Brasileiro

limbs and for balance after a protocol using a frequency of 30 Hz and amplitude of 10 mm. They suggest that this improved performance immediately after the vibrating stimulus might be related to an increase in stretch reflex sensitivity. 13 Stewart et al 14 also found increased isometric peak torque

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Takumi Kobayashi, Takeshi Mizota, Kana Kon, Miku Kasaya, Shogo Miyabe, Tomo Shindome, and Kousuke Ishibashi

) was used for statistical analysis, and a P value <.05 was considered significant. Experiment 2 The intraexaminer and interexaminer reliabilities of the PFBT and the isometric ankle PF torque were compared between positive and negative PFBT cases in healthy adults to verify the concurrent validity in

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Mary Hellen Morcelli, Dain Patrick LaRoche, Luciano Fernandes Crozara, Nise Ribeiro Marques, Camilla Zamfolini Hallal, Mauro Gonçalves, and Marcelo Tavella Navega

gait speed. 7 , 8 Poor lower limb strength has been associated with slow gait speed and the likelihood of falling, making it an important predictor of functional status in older adults. 9 – 12 The association exists because joint torques at the hip, knee, and ankle are summed in a coordinated fashion

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Tyler M. Saumur, Jacqueline Nestico, George Mochizuki, Stephen D. Perry, Avril Mansfield, and Sunita Mathur

strength can be defined as the force-generating capacity of the muscle 4 and can be quantified using various measures of force or torque. Muscle power is the mechanical work performed by the muscle over time and the muscle’s ability to produce high-velocity movements. 5 Balance control, strength, and

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Ty B. Palmer, Jarrod Blinch, Ahalee C. Farrow, Chinonye C. Agu-Udemba, and Ethan A. Mitchell

et al., 2016 ; Pereira et al., 2018 ). Such fatigue effects combined with substantial age-related decreases in muscle strength and balance may impair locomotor function and increase the risk of falls and fall-related injuries in older individuals ( Morrison et al., 2016 ). Strength-based torque

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Mark Glaister, Colin Towey, Owen Jeffries, Daniel Muniz-Pumares, Paul Foley, and Gillian McInnes

with torque factors of 0.75 to 0.90 N·m·kg −1 . 3 – 9 With the exception of the findings of Woolf et al, 9 all have found no effect of caffeine on performance. Nevertheless, Anselme et al 10 and Glaister et al 11 observed a significant effect of caffeine on peak anaerobic power output as determined

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Noah X. Tocci, David R. Howell, Dai Sugimoto, Corey Dawkins, Amy Whited, and Donald Bae

High levels of torque placed on the upper body, and in particular the elbow, can result in greater injury risk as joint loading could exceed the yield points of dynamic and passive stabilizers of the elbow. 10 Kerut et al previously noted that signs of susceptibility to arm injury might begin

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Rodrigo R. Bini and Patria A. Hume

The accuracy of commercial instrumented crank systems for symmetry assessment in cycling has not been fully explored. Therefore, the authors’ aims were to compare peak crank torque between a commercial instrumented crank system and instrumented pedals and to assess the effect of power output on bilateral asymmetries during cycling. Ten competitive cyclists performed an incremental cycling test to exhaustion. Forces and pedal angles were recorded using right and left instrumented pedals synchronized with crank-torque measurements using an instrumented crank system. Differences in right (dominant) and left (nondominant) peak torque and asymmetry index were assessed using effect sizes. In the 100- to 250-W power-output range, the instrumented pedal system recorded larger peak torque (dominant 55–122%, nondominant 23–99%) than the instrumented crank system. There was an increase in differences between dominant and nondominant crank torque as power output increased using the instrumented crank system (7% to 33%) and the instrumented pedals (9% to 66%). Lower-limb asymmetries in peak torque increased at higher power-output levels in favor of the dominant leg. Limitations in design of the instrumented crank system may preclude the use of this system to assess peak crank-torque symmetry.