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.
Remco J. Baggen, Jaap H. van Dieën, Sabine M. Verschueren, Evelien Van Roie and Christophe Delecluse
Johan Pelssers, Christophe Delecluse, Joke Opdenacker, Eva Kennis, Evelien Van Roie and Filip Boen
This study evaluated “Every Step Counts!”—a 10-wk, structured walking intervention in a community-based senior organization—on promoting physical activity participation, fitness, and well-being among older adults (age ≥ 55 yr). The intervention prescribed pedometer-defined walks in weekly walking schedules. These were fitness-tailored and structured in walking load (intensity/volume) according to the principles of training progression. This intervention was offered as a social activity at meeting points of a community-based senior organization. Twenty-nine meeting points (n = 432) constituted the intervention condition. Ten meeting points (n = 148) formed the wait-list control condition. Measurements were organized at intervention start (pretest) and end (posttest). Intention-to-treat linear mixed models showed small positive intervention effects on physical activity, fitness, and aspects of well-being. These results confirm the effectiveness of structured walking interventions with systematic training progression and underscore the value of community-based senior organizations as intervention settings for older adults.
Evelien Van Roie, Christophe Delecluse, Joke Opdenacker, Katrien De Bock, Eva Kennis and Filip Boen
Two groups of sedentary older adults, participating in either a lifestyle physical activity intervention (LIFE, n = 60) or a structured exercise intervention (STRU, n = 60), were compared with a control group (CO, n = 66) in terms of physical fitness and cardiovascular risk factors. Participants in LIFE were stimulated to integrate physical activity into their daily routines and received an individualized home-based program. Participants in STRU completed 5 supervised training sessions every 2 wk in a fitness center. Both interventions lasted 11 months and focused on endurance, strength, flexibility, and postural/balance exercises. The results revealed that the interventions were equally effective in improving functional performance. STRU was more effective than LIFE in improving cardiorespiratory and muscular fitness. Limited effects emerged on cardiovascular risk, with STRU improving in total cholesterol and HDL. Consequently, interventions aiming at reducing cardiovascular risks among sedentary elderly should focus on long-term changes in physical activity behavior.
Peter Catteeuw, Werner Helsen, Bart Gilis, Evelien Van Roie and Johan Wagemans
The offside decision-making process of international and national assistant referees (ARs) was evaluated using video simulations. A Tobii T120 Eye Tracker was used to record the eye movements. Two hypotheses for explaining incorrect decisions were investigated, namely, the flash-lag effect and the shift of gaze. Performance differences between skill levels were also examined. First, results showed a bias toward flag errors for national ARs as expected by the flash-lag effect. Second, ARs fixated the offside line before, during, and after the precise moment the pass was given, implying there was no shift of gaze from the passer to the receiving attacker. Third, no differences were found in scan patterns between international and national ARs. In conclusion, international ARs seem to have found a strategy to better deal with the perceptual illusion resulting from the flash-lag effect. Based on their experience, they have learned to correct for this illusion, and, consequently, show fewer flag errors.