Search

Obtaining true maximum voluntary excitation appears to be more difficult in older populations than in young populations. The aims of this study were (1) to determine whether differences in maximum voluntary excitation obtained from maximum voluntary isometric contraction (MVIC) and (sub-)maximum voluntary dynamic contraction [(s-)MVDC] are age dependent, and (2) to determine how normalizing electromyographic signals to corresponding maximum voluntary excitations affects variance between participants and the likelihood of normalized signals exceeding 100%. MVIC, s-MVDC, and MVDC were recorded in 10 young women, and MVIC and s-MVDC were recorded in 19 older women. A significant age × contraction mode interaction effect was found for vastus lateralis (P =.04). In young women, MVDC elicited the highest maximum voluntary excitation for vastus lateralis and rectus femoris (P <.05). In older women, no differences in maximum voluntary excitation were found (P >.05). Normalization to dynamic contractions resulted in lower between-participant variance of electromyography amplitudes, though not for all muscles, and decreased the number of normalized signals exceeding 100% in young women. These findings indicate that differences in maximum voluntary excitation across contraction modes are age dependent. Therefore, one should be cautious when comparing normalized signals between age groups; however, overall dynamic contractions may be preferable over isometric contractions for normalization purposes. [ABSTRACT FROM AUTHOR]

Within the context of a globally aging population and associated age-related changes to social relationships and individual psycho-physiology, a coalition of mostly European Union (EU) organizations concerned with physical activity in older persons was formed in 2013. The coalition examined worldwide decreases in physical activity among older adults, and the resulting negative effects on health and function for those individuals. After holding expert panel meetings, the coalition developed recommendations about how to address macro- and microlevel changes to increase and sustain physical activity among older populations across Europe. The recommendations were then compiled into a consensus document called "the Rome Statement", aimed at older adults, policy makers, researchers, and private and public professionals. This article presents the Rome Statement and its recommendations, and discusses how the statement can be broadly disseminated, considered, and implemented. [ABSTRACT FROM AUTHOR]

Background. This randomized controlled study investigated the effects of 1-year whole-body vibration (WBV) training on isometric and explosive muscle strength and muscle mass in community-dwelling men older than 60 years. Methods. Muscle characteristics of the WBV group ([Eta] = 31, 67.3 [+ or -] 0.7 years) were compared with those of a fitness (FIT) group ([Eta] = 30, 67.4 [+ or -] 0.8 years) and a control (CON) group ([Eta] = 36, 68.6 [+ or -] 0.9 years). Isometric strength of the knee extensors was measured using an isokinetic dynamometer, explosive muscle strength was assessed using a counter movement jump, and muscle mass of the upper leg was determined by computed tomography. Results. Isometric muscle strength, explosive muscle strength, and muscle mass increased significantly in the WBV group (9.8%, 10.9%, and 3.4%, respectively) and in the FIT group (13.1%, 9.8%, and 3.8%, respectively) with the training effects not significantly different between the groups. No significant changes in any parameter were found in the CON group. Conclusion. WBV training is as efficient as a fitness program to increase isometric and explosive knee extension strength and muscle mass of the upper leg in community-dwelling older men. These findings suggest that WBV training has potential to prevent or reverse the age-related loss in skeletal muscle mass, referred to as sarcopenia.

Roelants, M., S.M.P. Verschueren, C. Delecluse, O. Levin, and V. Stijnen. Whole-body-vibration--induced increase in leg muscle activity during different squat exercises. J. Strength Cond. Res. 20(1):124-129. 2006.--This study analyzed leg muscle activity during whole-body vibration (WBV) training. Subjects performed standard unloaded isometric exercises on a vibrating platform (Power Plate): high squat (HS), low squat (LS), and 1-1egged squat (OL). Muscle activity of the rectus femoris, vastus lateralis, vastus medialis, and gastrocnemius was recorded in 15 men (age 21.2 [+ or -] 0.8 years) through use of surface electromyography (EMG). The exercises were performed in 2 conditions: with WBV and without (control [CO1) a vibratory stimulus of 35 Hz. Muscle activation during WBV was compared with CO and with muscle activation during isolated maximal voluntary contractions (MVCs). Whole-body vibration resulted in a significantly higher (p < 0.05) EMG root-mean-square compared with CO in all muscle groups and all exercises (between + 39.9 + 17.5% and +360.6 [+ or - 57.5%). The increase in muscle activity caused by WBV was significantly higher (p < 0.05) in OL compared with HS and LS. In conclusion, WBV resulted in an increased activation of the leg muscles. During WBV, leg muscle activity varied between 12.6 and 82.4% of MVC values. KEY WORDS. surface electromyography, vibration training, tonic vibration reflex, muscle strength

This study examined the impact of short-term (7-day), high-dose (0.35 g * [kg.sup.-1] * [d.sup.-1]) oral creatine monohydrate supplementation (CrS) on single sprint running performance (40 m, Key Words: fatigue, recovery, athletics