High-velocity Training Research Articles

Early Adaptations to Eccentric and High-Velocity Training on Strength and Functional Performance in Community-Dwelling Older Adults

The authors examined whether an eccentric training program or a high-velocity training program was more beneficial in regards to function and strength. Nineteen community-dwelling older adults, between the ages of 65 and 89 years, from a local senior center participated in the 8-week exercise program. All participants were randomly assigned to either an eccentric or a high-velocity training group. A doubly multivariate analysis of variance with 1 between-subjects factor and repeated measures was used to examine group and time differences. This analysis revealed that no differences existed between the groups (p > 0.05). However, there were within-group differences for both the high-velocity and the eccentric groups. For both groups, walking speed, 8-ft up-and-go time, chair stand, leg extension strength, leg curl strength, and leg press strength increased from preintervention to postintervention (p < 0.05). This suggests that a high-velocity training program provides similar results as an eccentric training program but with less total work. The eccentric training group trained at a higher percentage of their 1RM and tested with higher loads, which may suggest that a longer exercise program would show the eccentric training group to be stronger and more functional. Fitness practitioners dealing with an older adult population should focus on training with all types of training velocities. Not only are these types of training modalities safe for this population but they also can improve their ability to perform activities of daily living.

Effect of Different Pushing Speeds on Bench Press

The purpose of this study was to investigate the effect on muscular strength after a 3-week training with the bench-press at a fixed pushing of 80-100% maximal speed (FPS) and self-selected pushing speed (SPS). 20 resistance-trained subjects were divided at random in 2 groups differing only regarding the pushing speed: in the FPS group (n=10) it was equal to 80-100% of the maximal speed while in the SPS group (n=10) the pushing speed was self-selected. Both groups were trained twice a week for 3 weeks with a load equal to 85% of 1RM and monitored with the encoder. Before and after the training we measured pushing speed and maximum load. Significant differences between and within the 2 groups were pointed out using a 2-way ANOVA for repeated measures. After 3 weeks a significant improvement was shown especially in the FPS group: the maximum load improved by 10.20% and the maximal speed by 2.22%, while in the SPS group the effect was <1%. This study shows that a high velocity training is required to increase the muscle strength further in subjects with a long training experience and this is possible by measuring the individual performance speed for each load.

America's Oil Imports: A Self-Inflicted Burden

Burdensome dependence on crude oil imports is a key challenge for America's energy policy; its principal cause is excessive consumption of refined oil products, which is mainly the result of an inefficient automotive fleet, the virtual absence of diesel-powered cars, and the complete absence of modern high-velocity trains. Addressing these challenges will require major infrastructural investment, a reality that precludes any early attainment of energy independence.

Improving Measures of Function Using an Inexpensive High Velocity Training Program

Research suggests that high velocity resistance training is a more advantageous way to improve certain functional measures, and reduce the risk of disablement in older adults. The training protocols associated with these results have utilized pneumatic exercise training equipment that may not be cost effective or accessible to the majority of the older adult population. PURPOSE: The purpose of this study is to see if a high velocity training program, using ankle weights, can improve measures of function in community dwelling functionally limited older adults. METHODS: Twenty two older adults (15 F, 7 M) over the age of 70 participated in the study with mean (± SD) age at 84.64 ± 6.85 years. All participants were free of cardiovascular, pulmonary, and metabolic disease and completed an informed consent. Participants were screened for mobility limitations using the Short Physical Performance Battery, and those included received a score of 10 or below, making them functionally limited. All participants were tested three times during the 12-week exercise intervention (pre-intervention, mid-intervention, and post-intervention) on dynamic balance, maximal walking speed, 8-foot up-and-go, and chair stand. The training consisted of two days per week for 12 weeks, and all exercises were progressed using ankle weights. The exercises performed were standing hip flexion, standing hip extension, standing heel raises, and chair stand. RESULTS: A one-way repeated measures analysis of variance was used to analyze the data to see if within group differences existed on the aforementioned variables. Statistical significance was α =.05. Results indicated that significant time effects existed on the chair stand variable, F (2, 42) = 19.52, p <.01. Post-hoc analysis revealed that within the chair stand variable, both time points had significant effects, time 1 to time 2, F (2, 42) = 20.16, p <.01, and time 1 to time 3, F (2, 42) = 34.24, p <.01. CONCLUSION: Although significant time effects were not seen in all of the variables tested, individual changes were noted from pre to post testing. For the maximal walking speed variable, 15 of the 22 older adults improved or maintained the same speed with some individuals showing a 20% to 30% improvement. This suggests that an inexpensive exercise program can improve measures of function in older adults.

Changes In Postactivation Potentiation At The Onset Of Exercise Training In Older Adults

INTRODUCTION Postactivation potentiation (PAP) of resting twitch force is known to decline with age (Vandervoort and McComas, 1986). The inability to utilize enhanced muscular output may contribute to impaired motor function in the elderly. In daily tasks, older adults seldom experience the high-force muscular contractions that elicit PAP. PURPOSE The purpose of this experiment was to determine the extent to which PAP is recoverable in older adults due to exercise training. For specific applications to frail elderly adults, a low-force, high movement velocity training intervention was tested. The goal of this training protocol was to elicit a high volume of neural activation, which might have a positive impact on PAP and other neuromuscular factors. METHODS Seventeen healthy older adults, (7 males, 10 females; mean ± standard deviation: age 76±6.3 yrs.), who were not actively participating in a strength-training program involving dorsi/plantar flexion exercises, participated in this study. Each subject was required to attend three sessions, each 48 hours apart. At the start of each session subjects were evaluated for PAP by applying supramaximal stimuli to the tibial nerve before and after a 10 second maximal voluntary isometric contraction. Stimuli were applied three times within each of two stimulus trains in which the stimuli were separated by 2 seconds and the trains by approximately 3 seconds. Thus PAP was the difference between the average peak torques of 6 twitches. The training was conducted after testing on both days one and two and consisted of 4 exercises; up-tempo cycling, two plantar flexion exercises, and active and passive ankle rotations. RESULTS Older adults exhibited an average of 24.5 ± 17.7 % PAP at baseline. This is similar to the results of Petrella et al. (1989). In response to the combined effects of training and test contractions, there was a significant increase in PAP (F2.32=3.850, p=0.032). There was an 18.5% increase in PAP from day 1 to day 2, and a 37.0% increase from day 1 to day 3 (D1=24.5±17.7; D2=29.1±16.6; D3=33.6±16.9) There were no significant changes in resting twitch torque, or maximal voluntary torque in this group. CONCLUSIONS These results indicate that PAP is trainable in older adults. It must be noted however, that due to requirements for other aspects of this experiment, training stimuli included maximal voluntary contractions. Thus, we cannot isolate the low-resistance exercises as the only candidate stimuli for increased PAP.

Isokinetic Exercise Training and Evaluation System Aimed High Velocity Training (The System Using ER Brake)

Isokinetic Exercise Training and Evaluation System Aimed High Velocity Training (The System Using ER Brake)

Research at DLR Göttingen on bluff body aerodynamics, drag reduction by wake ventilation and active flow control

This paper outlines some experimental investigations on aerodynamics of bluff bodies which have been carried out at the former DLR Institute of Fluid Mechanics, now Institute of Aerodynamics and Flow Technology. Examples given here include (a) drag reduction by passive ventilation of the wake of the body, (b) reduction of the drag of automobiles by shape optimisation to eliminate or at least decrease trailing vortices, (c) optimisation of front and rear ends of high speed trains, (d) determination of the main sources of aerodynamic noise of high velocity trains which result from unsteady flow separations, (e) experiments on active flow control to delay flow separation.

Velocity training induces power-specific adaptations in highly functioning older adults

Earles DR, Judge JO, Gunnarsson OT. Velocity training induces power-specific adaptations in highly functioning older adults. Arch Phys Med Rehabil 2000;82:872-8. Objective: To test the efficacy of high-velocity training in healthy older persons. Design: A 12-week randomized trial, with subjects blocked for gender and residence, comparing high-velocity resistance training with a self-paced walking program. Setting: Retirement community. Participants: Forty-three volunteers over the age of 70 years. Intervention: Power group: high-velocity leg exercises 3 times weekly with weekly increases in resistance combined with 45 minutes of moderate, nonresistance exercise weekly. Walking group: moderate intensity exercise 30 minutes daily, 6 days weekly. Main Outcome Measures: Variables measured included leg press peak power and leg extensor strength. Functional performance outcomes included: 6-minute walk distance, Short Physical Performance Battery, Physical Performance Test, and Medical Outcomes Study Short-Form Health Survey. Results: Peak power improved 22% (p =.004) in the power group (3.7 ± 1.0W/kg to 4.5 ± 1.4W/kg) but did not change in the walking group (3.99 ±.76W/kg to 3.65 ±.94W/kg). Leg extensor power at resistance of 50%, 60%, and 70% of body weight increased 50%, 77%, and 141%, respectively, in the power group (p <.0001, repeated-measures analysis of variance). Strength improved 22% in the power-trained individuals and 12% in the walkers (p <.0001). Training did not improve functional task performance in either group. One subject developed a radiculopathy during training. Conclusions: Resistance training focusing on speed of movement improved leg power and maximal strength substantially, but did not improve functional performance in healthy high-functioning older volunteers. © 2001 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Physical performance differences between weight-trained sprinters and weight trainers

The present study tested and compared well-trained athletes who were performing low-velocity, high-force resistance training and sprint running training (ST) when recruited, with subjects who were performing low-velocity, high-force resistance training but not sprint training (NST) when recruited. Eleven male sprint runners (mean +/- SD; age = 19.0 +/- 1.4 yr: height = 182.0 +/- 4.7 cm: mass = 75.7 +/- 4.7 kg), and eight male weight-trained athletes who were not currently performing sprint training, or any other additional training, (mean + SD; age = 21.5 +/- 1.8 yr: height = 184.5 +/- 3.6 cm: mass = 78.4 +/- 4.6 kg) participated in the study; all subjects had a minimum of two years resistance training experience. Tests included 1. running speed (20 m time after a 50 m acceleration distance and 20 m acceleration time from a stationary start), 2. isokinetic hip flexor/extensor torque (and torque adjusted for body mass), angle of peak torque, time to reach peak torque and torque acceleration energy at low (1.05 rad x s(-1) [60 degrees x s(-1)), moderate (4.74 rad x s(-1) [270 degrees x s(-1)) and high (8.42 rad x s(-1) [480 degrees x s(-1)) speeds and 3. maximum squat lift. ST subjects produced more isokinetic hip extensor torque when adjusted for body mass at 4.74 rad x s(-1) (270 degrees x s(-1); p<0.05) and reached their peak torque faster (p<0.05). ST subjects also produced more hip flexor torque at 8.42 rad x s(-1) (480 degrees x s(-1); p<0.05), and torque per body mass at 4.74 rad x s(-1) (270 degrees x s(-1)) and 8.42 rad x s(-1) (480 degrees x s(-1); p<0.05) and reached peak flexor torque faster than NST subjects (4.74 rad x s(-1) [270 degrees x s(-1)], p<0.05; 8.42 rad x s(-1) [480 degrees x s(-1), p<0.01). Further, ST subjects performed better in tests of running acceleration over 20 m (p<0.02) and achieved a higher maximum running velocity after a 50 m acceleration distance (p<0.001). No significant differences were found in isokinetic strength at low (1.05 rad x s(-1) [60 degrees x s(-1)) velocities or in maximal squat lift strength. The results of the present study suggest that athletes who perform low-velocity, high force training concurrently with high-velocity training are superior in tests of isokinetic strength at high velocities when compared to athletes who only perform low-velocity, high force training. This may be due to training or genetic factors.

Calculation of the 3D nonlinear eddy current field in moving conductors and its application to braking systems

This paper presents a complete FE formulation for the calculation of 3D nonlinear eddy current fields with ferromagnetic moving conductors. The formulation is realized by using the A/spl I.oarr/, V-A/spl I.oarr/ formulation in combination with the Coulomb gauge. To consider nonrectangular shapes of geometries tetrahedral elements were employed. The computation procedure is applied to an eddy current braking system of a high velocity train and the resulting braking forces are compared to measurements.

Influence of high-resistance and high-velocity training on sprint performance

The purpose of this study is to analyze the effect of high-resistance (HR) and high-velocity (HV) training on the different phases of 100-m sprint performance. Two training groups (HR and HV) were compared with two control groups (RUN and PAS). The HR (N = 22) and HV group (N = 21) trained 3 d.wk-1 for 9 wk: two strength training sessions (HR or HV) and one running session. There was a run control group (RUN, N = 12) that also participated in the running sessions (1 d.wk-1) and a passive control group (PAS, N = 11). Running speed over a 100-m sprint was recorded every 2 m. By means of a principal component analysis on all speed variables, three phases were distinguished: initial acceleration (0-10 m), building-up running speed to a maximum (10-36 m), and maintaining maximum speed in the second part of the run (36-100 m). HV training resulted in improved initial acceleration (P < 0.05 compared with RUN, PAS, and HR), a higher maximum speed (P < 0.05 compared with PAS), and a decreased speed endurance (P < 0.05 compared to RUN and PAS). The HV group improved significantly in total 100 m time (P < 0.05 compared with the RUN and PAS groups). The HR program resulted in an improved initial acceleration phase (P < 0.05 compared with PAS).

Validated computational aerodynamics for trains

Energy saving is a major issue for trains, especially since high velocity trains have been developed. One of the major parameters in mastering energy consumption in trains is directly related to the aerodynamics both in open environment and in special locations where the surroundings of the trains are restricted. The paper presents an advanced computational method for analyzing aerodynamics effects around trains in any environment. Several industrial application examples are described.

Velocity specificity of resistance training.

Velocity specificity of resistance training has demonstrated that the greatest strength gains occur at or near the training velocity. There is also evidence that the intent to make a high speed contraction may be the most crucial factor in velocity specificity. The mechanisms underlying the velocity-specific training effect may reside in both neural and muscular components. Muscular adaptations such as hypertrophy may inhibit high velocity strength adaptations due to changes in muscle architecture. However, some studies have reported velocity-specific contractile property adaptations suggesting changes in muscle kinetics. There is evidence to suggest velocity-specific electromyographic (EMG) adaptations with explosive jump training. Other researchers have hypothesised neural adaptations because of a lack of electrically evoked changes in relation to significant voluntary improvements. These neural adaptations may include the selective activation of motor units and/or muscles, especially with high velocity alternating contractions. Although the incidence of motor unit synchronisation increases with training, its contribution to velocity-specific strength gains is unclear. However, increased synchronisation may occur more frequently with the premovement silent period before ballistic contractions. The preprogrammed neural circuitry of ballistic contractions suggests that high velocity training adaptations may involve significant neural adaptations. The unique firing frequency associated with ballistic contractions would suggest possible adaptations in the frequency of motor unit discharge. Although co-contraction of antagonists increases with training and high velocity movement, its contribution is probably related more to joint protection than the velocity-specific training effect.

Intended rather than actual movement velocity determines velocity-specific training response.

Eight men and eight women trained 3 days/wk for 16 wk by doing attempted ballistic unilateral ankle dorsiflexions against resistance that either rendered the resultant contractions isometric (one limb) or allowed a relatively high-velocity (5.23 rad/s on an isokinetic dynamometer) movement (other limb). Training sessions consisted of five sets of 10 contractions of each type. Training produced the same high-velocity-specific training response in both limbs (P < 0.001). Peak torque increased most at 5.23 rad/s (38%) in comparison to lower velocities (0, 0.26, 0.52, 1.04, 1.55, 3.02, and 4.19 rad/s). Both limbs also showed similar increases in voluntary isometric rate of torque development (26%) and relaxation (47%) and in evoked tetanus rate of torque development (14%). A similar decrease in evoked twitch time to peak torque (6%) and half-relaxation time (11%) was also observed. Thus, all of these training responses, previously associated specifically with high-velocity resistance training, were produced by a training regimen that prevented an actual rapid movement through a range of movement. The results suggest that the principal stimuli for the high-velocity training response are the repeated attempts to perform ballistic contractions and the high rate of force development of the ensuing contraction. The type of muscle action (isometric or concentric) appears to be of lesser importance.

The Influence of Velocity-Specific Resistance Training on the In Vivo Torque-Velocity Relationship and the Cross-Sectional Area of Quadriceps Femoris

This work was supported by Sport Canada end Hydra-Fitness Industries. In order to investigate the effects of velocity-specific resistance training, 30 healthy, male varsity athletes were assigned to either high (HVR) or low (LVR) velocity training or control (CG) groups. Subjects completed two 20-sec sets of maximal exercise at each of six hydraulic resistance stations for the lower limb. Resistances were adjusted as necessary to maintain consistent average angular velocities of approximately 1.05 and 3.14 rad/sec for the LVR and HVR groups, respectively. Subjects trained on alternate days for 6 weeks, completing either two (weeks 1 and 2) or three (weeks 3-6) circuits of the six stations each session. Peak knee extension torques were improved (p < 0.05) for the LVR group at all of seven angular velocities tested between 1.05 and 4.19 rad/sec. Improvements (p < 0.05) were also observed for the HVR group, but only at angular velocities of 2.62, 3.14, 3.66, and 4.19 rad/sec. Cross-sectional area of the quadriceps femoris muscle group obtained from serial computer tomography (CT) scans was increased (p < 0.05) for both training groups. No significant changes in either strength or cross-sectional area were observed for control subjects. These results indicate that while both of the training programs resulted in increased cross-sectional area of the knee extensors, the observed changes in strength performance are likely due to other factors which may be mediated by the different training velocities. J Orthop Sports Phys Ther 1989;10(11):456-462.