is to demonstrate not how much, but how little, the organization has changed, generally since its inauguration in 1904 and particularly since the radical changes in Formula 1 in the 1970s, with regards to stakeholder policy and power management. Therefore, drawing on archival sources as well as
The author derived the exact analytical expression of the instantaneous joint power in exercises with single-joint, variable-resistance, selectorized strength-training equipment, taking into account all the relevant geometric, kinematic, and dynamic variables of both the movable equipment elements (resistance input lever, cam–pulley system, weight stack) and of the user’s exercising limb. A numerical algorithm was also designed to express, in the presence of a cam, the rectilinear kinematic variables of the weight stack as a function of the rotational kinematic variables of the resistance input lever, and vice versa. Given that information, one can measure the value of the instantaneous and mean joint power exclusively by means of a linear encoder placed on the weight stack or, alternatively, only by the use of an angular encoder placed on the rotational axis of the resistance lever. The results highlight that, for knee extension exercises with leg extension equipment, the real values of both instantaneous and mean joint power may differ by more than 50% in comparison with the values obtained by taking into account only the mass and velocity of the weight stack. These differences are notable not only in explosive exercises, but also whenever considerable joint velocities/accelerations occur within the range of motion.
Assane E.S. Niang and Bradford J. McFadyen
The present study investigated the adaptations of specific power bursts during the combined contexts of the proximity (lead vs. trail limb) and height of an obstruction in relation to limb elevation versus progression. Ten young, adult, male subjects walked at their natural speed during unobstructed walking and the bilateral avoidance of moderate and high obstacles. Hip flexor generation power was unaffected by obstacle height for the leading limb and always delayed for the trailing limb. The knee extensor absorption power burst at toe-off was also eliminated for the trailing limb and was found to reappear in mid-swing. Few differences were seen for ankle push-off power. The results suggest that the hip joint is dedicated to limb advancement only, while the knee joint is directly involved in limb elevation and the control of multiarticular effects.
Michal Wilk, Michal Krzysztofik, Milosz Drozd and Adam Zajac
Resistance training is one of the key components influencing power output. Previous studies directed at power development through the use of post-activation potentiation (PAP) have analyzed resistance exercises at volitional or fast tempo of movement in the entire cycle. without control of the duration of the concentric and eccentric phases of the movement. To date, no scientific studies have explored the effects of varied movement tempo on the level of power output, velocity and PAP efficiency.
During the experimental sessions, study participants performed three sets (Sets1-3) of the bench press (BP) exercise using 70% 1RM and two different tempos of movement: 2/0/X/0 eccentric medium tempo (ECCMED), and 6/0/X/0 eccentric slow tempo (ECCSLO).
Post-hoc analysis demonstrated significant differences in values of peak (PPEAK) and mean power (PMEAN) between Sets1-3 measured for the ECCMED (2/0/X/0) tempo. The values of PMEAN in Set3 (492.15 ± 87.61 W) were significantly higher than in Set2 (480.05 ± 82.10 W) and Set1 (467.65 ± 79.18 W). Similarly, the results of PPEAK in Set3 (713.10 ± 132.72 W) were significantly higher than those obtained in Set2 (702.25 ± 129.5 W) and Set1 (671.55 ± 115.79 W). For the ECCSLO tempo (6/0/X/0) in Set2 (587.9 ± 138.48 W), the results of PPEAK was significantly higher than in Set1 (565.7 ± 117.37 W) and Set3 (563.1 ± 124.93 W).
The results of this study indicate that the PAP effect is observed, for both, slow and medium tempo of movement.
Florian Hemme and Marlene A. Dixon
James Park has been hired as the new CEO by the board of directors of GoSports Inc., a large national sporting goods retailer, which has been battling economic and internal issues over the previous years. Despite Park’s experience at the helm of large companies in need of profound strategic and structural change, in his new position at GoSports he has been “butting heads” with a powerful collective of executives unhappy with the hire and threatened by the new CEO’s accolades. To complicate matters, rumor has it that the decision to hire Park was far from unanimous, with various factions vying for control in the company, waiting for a chance to fill the power vacuum a quick departure by Park would leave behind. After two weeks with the company, Park is called before the board of directors to report on the progress made and how he plans to return GoSports to its former glory.
Nuria Garatachea, Zoraida Verde, Alejandro Santos-Lozano, Thomas Yvert, Gabriel Rodriguez-Romo, Francisco J. Sarasa, Sonsoles Hernández-Sánchez, Catalina Santiago and Alejandro Lucia
To determine the association of the ACTN3 R577X polymorphism with leg-muscle explosive power in Spanish (white) elite basketball players and controls.
100 (60 men) elite basketball players (cases) and 283 nonathletic controls.
The authors assessed power performance by means of the vertical-squat and countermovement-jump tests.
Genotype distributions did not differ between groups (cases: 37.0% [RR], 42.0% [RX], and 21.0% [XX]; controls: 31.8% [RR], 49.8% [RX], and 18.4% [XX]; P = .353). The authors did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in either group, including when they performed the analyses separately in men and women. They found no association between the ACTN3 R577X polymorphism and the likelihood of being an elite basketball player using the dominant or the recessive model, and the results remained unaltered when the analyses were adjusted for sex, weight, height, and age or when performed for men and women separately.
Although the ACTN3 R577X is associated with explosive muscle performance and this phenotype is important in the sport of basketball (ie, during jumps), the authors found no association with leg explosive power in elite basket players or with the status of being this type of athlete.
Thomas Haugen, Gøran Paulsen, Stephen Seiler and Øyvind Sandbakk
external power output underlie successful performance in sports. Accordingly, regular assessment of aerobic and anaerobic power informs the overall training strategy of most of today’s elite athletes. Numerous groups have reported contemporary power data from elite athletes, particularly runners, cyclists
Emma K. Zadow, Cecilia M. Kitic, Sam S.X. Wu and James W. Fell
Advancements in the technology of cycling ergometers have been shown to provide increasing accuracy in the measurement of power output. The measurement of power is an important determinant of performance and is vital for evaluating individual differences in performances, monitoring the
Jason D. Stone, Adam C. King, Shiho Goto, John D. Mata, Joseph Hannon, James C. Garrison, James Bothwell, Andrew R. Jagim, Margaret T. Jones and Jonathan M. Oliver
), elicits a near linear decline in barbell velocity, and thus power output. 3 – 5 Recognizing that force and velocity are both required to maintain a given work capacity, muscular fatigue has been defined as the inability to maintain the required or expected power output. 6 Attenuated power production is
Seiichiro Takei, Kuniaki Hirayama and Junichi Okada
Olympic weight-lifting exercises are among the most powerful movements in sport and are often used by athletes for power enhancement along with other primary power exercises like plyometrics and jump squats. 1 Among weight-lifting exercises, the hang power clean (HPC) is a widely used exercise in