Maximum strength and rate of force development (RFD) are 2 important strength characteristics for everyday tasks and athletic performance. Measurements of both parameters must be reliable. Expensive isokinetic devices with isometric modes are often used. The possibility of cost-effective measurements in a practical setting would facilitate quality control. The purpose of this study was to assess the reliability of measurements of maximum isometric strength (Fmax) and RFD on a conventional leg press. Sixteen subjects (23 ± 2 y, 1.68 ± 0.05 m, 59 ± 5 kg) were tested twice within 1 session. After warm-up, subjects performed 2 times 5 trials eliciting maximum voluntary isometric contractions on an instrumented leg press (1- and 2-legged randomized). Fmax (N) and RFD (N/s) were extracted from force-time curves. Reliability was determined for Fmax and RFD by calculating the intraclass correlation coefficient (ICC), the rest-retest variability (TRV), and the bias and limits of agreement. Reliability measures revealed good to excellent ICCs of .80-.93. TRV showed mean differences between measurement sessions of 0.4-6.9%. The systematic error was low compared with the absolute mean values (Fmax 5-6%, RFD 1-4%). The implementation of a force transducer into a conventional leg press provides a viable procedure to assess Fmax and RFD. Both performance parameters can be assessed with good to excellent reliability allowing quality control of interventions.
Heiner Baur, Alessia Severina Groppa, Regula Limacher and Lorenz Radlinger
Paul A. Solberg, Will G. Hopkins, Gøran Paulsen and Thomas A. Haugen
Purpose: To quantify age of peak performance and performance improvements in the years preceding peak age in elite weightlifting and powerlifting athletes using results from powerlifting World Championships in 2003–2017 and weightlifting World Championships and Olympic Games in 1998–2017. Methods: Individual performance trends were derived by fitting a quadratic curve separately to each athlete’s performance and age data. Effects were evaluated using magnitude-based inferences. Results: Peak age (mean [SD]) was 35 (7) y for powerlifters and 26 (3) y for weightlifters, a large most likely substantial difference of 9, ±1 y (mean, 90% confidence limit). Men showed possibly higher peak age than women in weightlifting (0.8, ±0.7 y; small) and a possibly lower peak age in powerlifting (1.3, ±1.8 y; trivial). Peak age of athletes who ever won a medal was very likely less than that of nonmedalists in weightlifting (1.3, ±0.6 y; small), while the difference in powerlifters was trivial but unclear. Five-year improvements prior to peak age were 12% (10%) for powerlifters and 9% (7%) for weightlifters, a small possibly substantial difference (2.9, ±2.1%). Women exhibited possibly greater improvements than men in powerlifting (2.7, ±3.8%; small) and very likely greater in weightlifting (3.5, ±1.6%; small). Medalists possibly improved less than nonmedalists among powerlifters (−1.7, ±2.3%; small), while the difference was likely trivial for weightlifters (2.3, ±1.8%). Conclusion: These novel insights on performance development will be useful for practitioners evaluating strategies for achieving success.
Steven L. Fischer, Bryan R. Picco, Richard P. Wells and Clark R. Dickerson
Exerting manual forces is critical during occupational performance. Therefore, being able to estimate maximum force capacity is particularly useful for determining how these manual exertion demands relate to available capacity. To facilitate this type of prediction requires a complete understanding of how maximum force capacity is governed biomechanically. This research focused on identifying how factors including joint moment strength, balance and shoe-floor friction affected hand force capacity during pulling, pressing downward and pushing medially. To elucidate potential limiting factors, joint moments were calculated and contrasted with reporte joint strength capacities, the balancing point within the shoe-floor interface was calculated and expresess relative to the area defined by the shoe-floor interface, and the net applied horizontal forces were compare with the available friction. Each of these variables were calculated as participants exerted forces in a series o conditions designed to systematically control or restrict certain factors from limiting hand force capacity. The results demonstrated that hand force capacity, in all tested directions, was affected by the experimental conditions (up to 300%). Concurrently, biomechanical measures reached or surpassed reported criterion threshold inferring specific biomechanical limitations. Downward exertions were limited by elbow strength, wherea pulling exertions were often limited by balance along the anterior-posterior axis. No specific limitations wer identified for medial exertions.
Aaron T. Scanlan, Neal Wen, Joshua H. Guy, Nathan Elsworthy, Michele Lastella, David B. Pyne, Daniele Conte and Vincent J. Dalbo
fixed position indicative of the second pull during the power clean lift. 4 Peak force is a useful outcome measure obtained during the IMTP and is indicative of strength capacity. 8 Given power is a function of force production and velocity, well-developed strength attributes may be advantageous for
Anthony C. Santago II, Meghan E. Vidt, Xiaotong Li, Christopher J. Tuohy, Gary G. Poehling, Michael T. Freehill and Katherine R. Saul
capacity of the shoulder. All functional tasks require a minimum strength below which successful performance is not possible 28 ; strength capacity above this limit is referred to as reserve strength. 28 Even with the age- and tear-related declines in strength capacity, older adults in this study
Aitor Iturricastillo, Cristina Granados, Raúl Reina, José Manuel Sarabia, Ander Romarate and Javier Yanci
Although in conventional team sports, upper-limb strength capacity has been widely determined by means of the bench press (BP), 11 , 12 in Para-sports, few studies have analyzed this exercise to determine muscle strength. 7 – 9 , 13 However, one of the main problems faced by strength and conditioning
Anthony Birat, David Sebillaud, Pierre Bourdier, Eric Doré, Pascale Duché, Anthony J. Blazevich, Dimitrios Patikas and Sébastien Ratel
heights were increased from 20 to 70 cm compared with the SJ, and that explosive strength capacities (measured as the RSI) were significantly reduced when drop heights were 60 cm or higher. However, a count of the number of subjects who produced their best performance at each drop height revealed that
Scott R. Brown, Erin R. Feldman, Matt R. Cross, Eric R. Helms, Bruno Marrier, Pierre Samozino and Jean-Benoît Morin
the observed increases in mechanical sprint measures. Importantly, this case study was the first of knowledge to show that a training regime, predominantly targeting hip extensor strength capacities, reduced F H asymmetry. This finding is of note, given the prevalence of posterior chain injuries
Irineu Loturco, Timothy Suchomel, Chris Bishop, Ronaldo Kobal, Lucas A. Pereira and Michael McGuigan
, according to the objectives and needs of a given athlete or sport discipline. 1 , 2 For example, programs designed to develop maximum strength capacity tend to adopt loading ranges varying between 80% and 100% 1RM, whereas programs focused on developing muscle power normally prioritize the use of exercises
Pedro Jiménez-Reyes, Amador García-Ramos, Victor Cuadrado-Peñafiel, Juan A. Párraga-Montilla, José A. Morcillo-Losa, Pierre Samozino and Jean-Benoît Morin
present a higher F 0 and a lower V 0 , because a larger number of short-distance accelerations are typically performed during futsal competitions compared with soccer. 18 , 19 Due to the well-known differences in strength capacities between men and women 20 and to the fact that sprint ability has