Training for Old Age: Production Functions for the Aerobic Exercise Inputs

Purpose: This paper attempts to develop production functions (PF) between aerobic exercise inputs and long-run health outputs. Future studies could use such PF for estimating the benefits and costs (broadly defined) of different exercise programs to help develop optimal (utility maximizing) ones. Methods: To develop the PF, the paper reviewed the biomedical literature for the major dose-response relations between health, physical fitness, and exercise. Where relevant, the paper converted the dose-response relationships from relative risks to absolute probabilities and standardized terminology and units of measures. Results: The paper develops a clear set of biological PF that illustrate, quantitatively, how increases in peak cardiorespiratory (CR) fitness as measured by a short stress test reduce the probability of all-cause mortality; how increasing intensities of short (approximately 30 min, three to five times a week) exercise sessions increase peak CR fitness or retard its age-related decline; and how consistent exercise reduces the risk of myocardial infarctions (MI). Conclusions: The exercise-long-run health PF developed in this paper should provide a useful framework for other studies to estimate the broadly defined costs and benefits of different exercise programs and to help develop optimal ones

Reliability and Validity of a Pressure Algometer

Algometers are devices that can be used to identify the pressure and/or force eliciting a pressure-pain threshold. It has been noted in pressure-pain threshold studies that the rate at which manual force is applied should be consistent to provide the greatest reliability. This study tested the reliability and construct validity of an algometer (1000-Hz sampling rate) by manually applying pressure on a force plate (500-Hz sampling rate): 10 sets of 5 applications to 80 N and 1 set of 5 applications to each force level: 20, 30, 40, 50, 60, 70, 80, 90, 100, and 110 N. The investigator had previously become familiar with and practiced with the algometer. The handheld algometer had a 1-cm2 round rubber application surface, and the maximum force reading was compared with maximum force readings by the force plate using SEM and t-tests. Force-time curves were analyzed for average slope representing rate of force application. Average Pearson (r) correlations between the maximum force reading of the algometer and force plate were excellent in both trials to 80 N (r = 0.990) and the incremental trials (r = 0.999). The application of force was reasonably constant, with slopes averaging 6.8 ± 0.932 N·s−1. The SEE was 0.323 N. In conclusion, with previous familiarization and practice, an investigator may have high reliability in the rate of force application. The device itself was also highly correlated with readings from a force plate and, therefore, may be considered valid

Effect of Vibration on Forward Split Flexibility and Pain Perception in Young Male Gymnasts

Purpose: To continue investigation of the use of vibration to enhance acute range of motion while assessing the influence of vibration and stretching on pressure-to-pain threshold perception. Methods: Ten young male gymnasts were assessed for split range of motion. One side split was randomly assigned as the experimental condition, and the other side split was assigned as the control. Both side splits were performed on a vibration device; the experimental condition had the device turned on and the control condition was performed with the device turned off. In addition, the athletes were assessed for pressure-to-pain transition using an algometer on the biceps femoris (stretched muscle) and vastus lateralis (nonstretched muscle) bilaterally. Results: Pre-post difference scores between the vibrated split (most improved) and the nonvibrated split were statistically different (P = .001, 95% confidence interval of the difference 2.3 to 5.8 cm). Following the stretching protocol, the force values for the pressure-to-pain threshold comparing the vibrated and nonvibrated biceps femoris muscle were not statistically different. The nonstretched vastus lateralis muscle also showed no statistical difference in pressure-to-pain threshold between the vibration and nonvibration conditions. Conclusion: This study showed that vibration improved split range of motion over stretching alone, but did not show a difference in pressure-to-pain perception in either the stretched or nonstretched muscles

Stretching: Acute and Chronic? The Potential Consequences

Stretching is commonly used by many athletes in different sports. Although acute stretching, as part of a warm-up, can enhance range of motion, it may also reduce performance. Acute stretching can reduce peak force, rate of force production, and power output. Chronic stretching may enhance performance, although the mechanism is unclear. Acute stretching has little effect on injury. However, chronic stretching (not part of warm-up) may have some injury reduction potential

Vibration and Stretching Effects on Flexibility and Explosive Strength in Gymnasts

Abstract available in the Journal of Strength and Conditioning Researc

The Effect of 8 Weeks of Strength-power Training in Collegiate Throwers on Force-time Parameters Generated During a Post-exercise Potentiation Complex

Abstract available in the Journal of Strength and Conditioning Researc

Relationship Between Isometric Force Characteristics and Peak Power Output in Static and Countermovement Jumps at Various Loading Conditions

Abstract available in the Journal of Strength and Conditioning Researc

Vibration and Stretching Effects on Flexibility and Explosive Strength in Young Gymnasts

Purpose: Effects of simultaneous vibration-stretching on flexibility and explosive strength in competitive female gymnasts were examined. Methods: Twenty-two female athletes (age = 11.3 ± 2.6 yr; body mass = 35.3 ± 11.6 kg; competitive levels = 3-9) composed the simultaneous vibration-stretching (VS) group, which performed both tests. Flexibility testing control groups were stretching-only (SF) (N = 7) and vibration-only (VF) (N = 8). Explosive strength-control groups were stretching-only (SES) (N = 8) and vibration-only (VES) (N = 7). Vibration (30 Hz, 2-mm displacement) was applied to four sites, four times for 10 s, with 5 s of rest in between. Right and left forward-split (RFS and LFS) flexibility was measured by the distance between the ground and the anterior suprailiac spine. A force plate (sampling rate, 1000 Hz) recorded countermovement and static jump characteristics. Explosive strength variables included flight time, jump height, peak force, instantaneous forces, and rates of force development. Data were analyzed using Bonferroni adjusted paired t-tests. Results: VS had statistically increased flexibility (P) and large effect sizes (d) in both the RFS (P = 1.28 × 10−7, d = 0.67) and LFS (P = 2.35 × 10−7, d = 0.72). VS had statistically different results of favored (FL) (P = 4.67 × 10−8, d= 0.78) and nonfavored (NFL) (P = 7.97 × 10−10, d = 0.65) legs. VF resulted in statistical increases in flexibility and medium d on RFS (P = 6.98 × 10−3, d = 0.25) and statistically increased flexibility on VF NFL flexibility (P = 0.002, d = 0.31). SF had no statistical difference between measures and small d. For explosive strength, there were no statistical differences in variables in the VS, SES, and VES for the pre- versus posttreatment tests. Conclusions: Simultaneous vibration and stretching may greatly increase flexibility while not altering explosive strength

Isometric and Dynamic Force-time Curve Characteristics of Collegiate Throwers

Abstract available in theJournal of Strength and Conditioning Researc

Relationship Between Isometric Force Characteristics and the Difference in Jump Height in Weighted and Un-weighted Jumps

Abstract available in the Journal of Strength and Conditioning Researc