A rehabilitation protocol emphasising lengthening type of exercises is more effective than a protocol containing conventional exercises in promoting time to return in Swedish elite sprinters and jumpers.

Multidomain lifestyle interventions represents a promising strategy to counteract cognitive decline in older age. Brain-derived neurotrophic factor (BDnf) is essential for experience-dependent plasticity and increases following physical exercise, suggesting that physical exercise may facilitate subsequent learning. In a randomized-controlled trial, healthy older adults (65-75 years) completed a 12-week behavioral intervention that involved either physical exercise immediately before cognitive training (n = 25; 13 females), physical exercise immediately after cognitive training (n = 24; 11 females), physical exercise only (n = 27; 15 females), or cognitive training only (n = 21; 12 females). We hypothesized that cognition would benefit more from cognitive training when preceded as opposed to followed by physical exercise and that the relationship between exercise-induced increases in peripheral BDnf and cognitive training outcome would be greater when cognitive training is preceded by physical exercise. Greater increases of plasma BDnf were associated with greater cognitive training gains on trained task paradigms, but only when such increases preceded cognitive training (ß = 0.14, 95% CI [0.04, 0.25]). Average cognitive training outcome did not differ depending on intervention order (ß = 0.05, 95% CI [−0.10, 0.20]). The study provides the first empirical support for a time-critical but advantageous role for post-exercise increases in peripheral BDnf for learning at an interindividual level in older adults, with implications for future multidomain lifestyle interventions. Late-life cognitive impairment and dementia have increasingly serious human, social, and economic burdens, and prevention is a key element to counteract this development 1. Epidemiological studies have found that cognitive performance across the lifespan is associated with various lifestyle factors, including education 2 , occupational complexity 3 , and physical activity 4. Single-domain intervention studies have provided weak support for an advantageous role of cognitive training and physical exercise for cognition in older age, but effects tend to be small and inconsistent 5-8. It has consequently been suggested that multidomain interventions that target several lifestyle factors may be needed for optimal preventative effects 9. Mechanistic accounts for how such multidomain interventions should be designed to optimize effects are, however, largely lacking. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that is essential for neuronal plasticity 10,11 and increases transiently from physical exercise 12-14. BDNF can therefore be expected to be of mechanistic relevance for the interactive effects of physical exercise and cognitive training on cognition. Here we investigate the cognitive effects of a 12-week multidomain intervention comprising cognitive training and physical exercise, in close temporal succession, in healthy older adults, focusing on BDNF as a possible biological mechanism. Under conditions of physical exercise, the bra...

PurposeThe aim of this study was to describe thigh muscle activation during cycling using intramuscular electromyographic recordings of eight thigh muscles, including the biceps femoris short head (BFS) and the vastus intermedius (Vint).MethodsNine experienced cyclists performed an incremental test (start at 170 W and increased by 20 W every 2 min) on a bicycle ergometer either for a maximum of 20 min or to fatigue. Intramuscular electromyography (EMG) of eight muscles and kinematic data of the right lower limb were recorded during the last 20 s in the second workload (190 W). EMG data were normalized to the peak activity occurring during this workload. Statistical significance was assumed at p ≤ 0.05.ResultsThe vastii showed a greater activation during the 1st quadrant compared to other quadrants. The rectus femoris (RF) showed a similar activation, but with two bursts in the 1st and 4th quadrants in three subjects. This behavior may be explained by the bi-articular function during the cycling movement. Both the BFS and Vint were activated longer than, but in synergy with their respective agonistic superficial muscles.ConclusionIntramuscular EMG was used to verify muscle activation during cycling. The activation pattern of deep muscles (Vint and BFS) could, therefore, be described and compared to that of the more superficial muscles. The complex coordination of quadriceps and hamstring muscles during cycling was described in detail.

The purpose was to examine power output and three-dimensional (3D) kinematic variables in the upper limbs, lower limbs and trunk in elite flat-water kayakers during kayak ergometer paddling. An additional purpose was to analyse possible changes in kinematics with increased intensity and differences between body sides. Six male and four female international level flat-water kayakers participated. Kinematic and kinetic data were collected during three tasks; low (Int), high (Int) and maximal (Int) intensities. No differences were observed in any joint angles between body sides, except for shoulder abduction. Significantly greater range of motion (RoM) values were observed for Int compared to Int and for Int compared to Int in trunk and pelvis rotation, and in hip, knee and ankle flexion. The mean maximal power output was 610 ± 65 and 359 ± 33 W for the male and female athletes, respectively. The stroke frequencies were significantly different between all intensities (Int 59.3 ± 6.3; Int 108.0 ± 6.8; Int 141.7 ± 18.4 strokes/min). The results showed that after a certain intensity level, the power output must be increased by other factors than increasing the joint angular RoM. This information may assist coaches and athletes to understand the relationship between the movement of the kayaker and the paddling power output.

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