- Journal Details
- First Published
- 13 Jan 2009
- Publication timeframe
- 5 times per year
- Open Access
Page range: 5 - 22
The involvement of brain plastic mechanisms in the control of motor functions under normal and pathological conditions is described. These mechanisms are based on a similar principle as the neuronal models of neuronal plasticity - long-term potentiation (LTP), and long-term depression (LTD). In the motor cortex, LTP-like phenomena play a role in strengthening synaptic connections between pyramidal neurons. LTD is important for the elimination of unnecessary inputs to the cortex. The dynamic features of the primary motor cortex activity depend on particular neuronal interconnectivity within this area. The pyramidal cells send horizontal collaterals to adjacent subregions of the primary motor cortex, and so can either excite or inhibit remote pyramidal cells. These connections can expand or shrink depending on actual physiological demands, and play a role in skill learning.
- brain plasticity
- ischemic brain stroke
- motor cortex
- transcranial brain stimulation
- Open Access
Page range: 23 - 35
During the recent years it has been shown repeatedly that, after initial learning, elapse of time preserves, but sleep enhances performance in procedural motor skills. To date, however, the majority of experimental studies in this area employed some sort of a sequential finger tapping skill as a criterion task. Thus it is unclear yet, if any (and which) other types of motor skills do indeed benefit from sleep. In order to answer this question, and to provide theoretical statements about the memory system regarding benefits of sleep in motor learning, we carried out a series of studies following a "multi-task research strategy". Although we successfully replicated sleep-related improvements in the production of newly acquired sequential finger skills (FT-Task) under different learning conditions (i.e., guided or unguided), we did not find any such effect of sleep in discrete motor tasks requiring precise production of (a) a specific relative timing pattern (Diamond Tapping-Task), or (b) a sub-maximal force impulse (vertical Counter Movement Jump), and we also failed to find any specifically sleep-related effects on subsequent performance in (c) a continuous visuo-motor pursuit-tracking task. These results are considered in relation to other work, and the respective theoretical implications are discussed.
- motor learning
- Open Access
Page range: 37 - 50
Purpose: The purpose of this review is to present our recent findings related to the studies of hand function based on the coordination of forces exerted against hand-held objects.
Basic procedures: A novel device has been developed for recording grip (GF; acting perpendicularly at the hand-object contact) and load force (LF; acting tangentially) during uni- and bimanual manipulation tasks performed under either static or dynamic conditions. Both healthy participants and neurological patients were tested. The outcome measures were obtained from the task performance (i.e., the ability to exert accurate LF profiles), GF-LF coordination and GF modulation.
Main findings: The method applied proved to not only to be both reliable and valid, but also sufficient to detect differences between the dominant and non-dominant hand, as well as between healthy participants and mildly involved neurological patients. Marked differences in most of the depended variables were also detected between unidirectional and bi-direction tasks (i.e., in the tasks where LF acts in one and in two alternating directions). The later finding could not be based neural mechanisms known for their role in manipulative actions, such as on employing ad hoc muscle synergies or on the afferent activity of skin mechanoreceptors.
Conclusions: The employed methodological approach can be applied not only to explore various manipulation activities, but also to serve as a basis for future development of specific clinical tests for populations that demonstrate impaired hand function.
- Open Access
Page range: 51 - 61
The aim of the study was to conduct a preliminary evaluation of consecutive maximum contractions (CMC) as a test of neuromuscular function. Eleven participants performed externally paced isometric CMC (i.e., a series of consecutive maximum force exertions and relaxations) of the quadriceps muscle. The derived variables included the peak forces, and the maximum rates of force development and relaxation. The results revealed high within-day reliability of CMC variables, while their correlations with the jumping performance were consistently higher than those of the variables of the standard strength test (SST). CMC variables also showed fairly stable values across a wide range of frequencies, while their peak force revealed a strong relationship with maximum force of SST despite being about considerably lower. Therefore, we conclude that CMC could be developed into a standard test of neuromuscular function. In addition to capturing the muscle actions based on different neural activation pattern than SST, CMC could also be based on simpler testing procedure, lower force exertion, and self-selected frequencies.
- Open Access
Page range: 63 - 70
We investigated the effects of aging on postural muscles covariate patterns prior to voluntary perturbations. Nine healthy young and nine older subjects were instructed to release a load in a self-paced manner. The results of cross-correlation analyses showed that the average time lag corresponding peak correlation coefficient between trunk flexor and extensor muscles in the older group was significantly shorter, compared to that in the young group. The results of principal component analysis showed that the co-contraction Muscle-modes in the older group were observed more frequently than those in the young group. These results indicate that the older group showed changes in the anticipatory postural muscle co-variation, suggesting the transition from reciprocal to co-activation pattern with aging.
- postural stability
- Open Access
Page range: 71 - 80
Children, especially younger, are recognized as very susceptible to environmental lead exposure. In order to assess the effect of lead on spontaneous postural sway, we studied 327 children 4-13 years old, living in 4 cities in Upper Silesia an industrial region of Poland. Lead concentration in blood was measured by absorption atomic spectrometry (AAS) and posturography was performed using CATSYS 2000 - SWAY 7.0 equipment. Children's postural sway characteristics decreased with age. Particular variables had higher values for boys than girls and were positively associated with blood lead levels. There was an association between postural sway characteristics and smoking habits of mother, usage of aminoglycosides and paracetamol. Posturography seems to be a useful tool for assessment of lead exposure effects on the nervous system at low blood lead levels.
- environmental exposure to lead
- postural stability
- Open Access
Page range: 81 - 88
In the present study, we evaluated the plasma concentration of inflammatory mediators including cytokines and their relation with oxidative damage markers in training cycles of basketball players.
Sixteen professional players of the Polish Basketball Extraleague participated in the study. The basketball players were observed during the preparatory period and the play-off round. Twenty healthy and untrained males composed of the reference group.
The comparative study has shown significantly higher levels of lipid peroxidation (TBARS) and protein carbonylation (PC) in nonathletes than in basketball players during the observed training periods. Tumour necrosis factor α (TNFα), similarly to TBARS and PC, was significantly higher in nonathletes than athletes, except at the end of the play-off round. Interleukin-6 (IL-6) was lower in nonathletes than athletes in the preparatory period but it was higher in athletes in play-off round. In basketball players, the high level of IL-6 directly correlated with TBARS (r = 0.763, p<0.001) and PC (r = 0.636, p<0.001) during the preparatory period, whereas the high level of TNF α inversely correlated with TBARS (r = −0.601, p<0.001) and PC (r = −0.650, p<0.001) in the play-off round. The activity of creatine kinase (CK) was significantly increased during the training mezocycles in basketball players compared with nonathletes, and reached the highest activity at the end of the play-off round. CK activity did not correlate with oxidative damage markers and cytokines in both untrained and trained subjects.
Our results have shown the reduction in oxidative damage and improvement in cytokine response following professional training, as well as the relationship between inflammatory and pro-oxidative processes in basketball players.
- lipid peroxidation
- protein carbonylation
- Open Access
Effects of Long-term Regular Exercise on Cognitive Function, Lipid Profile and Atherogenic Biomarkers in Middle-aged Men
Page range: 89 - 98
Several studies on exercise and its effect on cognitive function in human and animal populations have documented the beneficial impact of regular physical activity on maintenance of good cognitive abilities and satisfactory health-related quality of life well into older age. The aim of the study was to evaluate the effects of long-term regular running on metabolic profile and cognitive function in middle-aged men.
A total of 24 regularly exercising, middle-age men (Group A), all being members of the Runners Club, and 22 age-matched sedentary subjects (Group B), as the control group, were enrolled in this study. The control group included 8 non-overweight (BMI=23.5±5.2) individuals (Group C) and 14 overweight/obese (BMI=30.7±1.6) subjects (Group D). Serum lipid profile, glucose and homocysteine concentrations were assessed by routine laboratory methods. Subjects' cognitive function was evaluated based on Trail Making Test (TMT) and Digit Symbol Test (DST) scores.
In a majority of runners (Group A), the BMI and the parameters of lipid profile (TC, HDL, LDL, TG, glycerol) were close to those recorded in non-overweight controls (Group C) and, in both groups, results were ideally within the reference ranges for healthy male subjects. However, as compared to the whole control group (Group B), which may be considered as an average population sample of sedentary middle-age men, significant differences were observed in BMI and concentrations of TC and LDL, as well as in the pro-atherogenic biomarkers (TC/HDL, LDL/HDL), which were lower in runners. A similar tendency was found in concentrations of TG (independent cardiovascular risk factor), glycerol and TG/HDL ratio (surrogate measure of insulin resistance), however the differences did not reach the level of significance. The level of homocysteine (pro-atherogenic biomarker) was comparable in all groups, and in most cases, within the reference range for male adults. Results of cognitive function tests did not reveal any significant between-group differences. The TMT score was found to be correlated positively (r=0.492, p<0.05), whereas DST score was correlated negatively (r=-0.549, p<0.005), with age. The DST performance, as evaluated in the group of runners (Group A), appeared to be strongly dependent (r=0.809, p<0.005) on the educational level of the subject.
These data provided evidence of beneficial effects of a long-term regular endurance running exercise on lipid profile and cardiovascular health in middle-aged men. However, we failed to confirm the findings of a favorable impact of regular physical activity on improvement in cognitive abilities.
- cognitive function
- lipid profile
- physical exercise
- Open Access
The Effects of Terminating Creatine Supplementation and Resistance Training on Anaerobic Power and Chosen Biochemical Variables in Male Subjects
Page range: 99 - 110
The main objective of this study was to investigate the effects of alkaline creatine supplementation and resistance training termination on anaerobic power and chosen biochemical variables in men. Twenty-three untrained male subjects, which participated in this study, were divided into supplemented (S) (n=13, age 21.4±2.3 y) and placebo (PL) (n=10, age 22.1±2.6 y) groups. The participants from both groups performed resistance training 3 times a week, while subjects from group S were supplemented with alkaline creatine (ACr) for 4 weeks on their training day's with 66.8 mg/kg b.m., and on non training day's with 33.8 mg/kg b.m.
To evaluate anaerobic power, the 30s Wingate test was applied. The following variables were registered: relative mean power - RMP (W/kg), relative peak power - RPP (W/kg), time of reaching peak power - TRPP (s) and relative total work - RTW (J/kg). The test was administrated 5 times - before and after 4 weeks of training and supplementation, as well as the first, second and third week after terminating creatine intake and the resistance exercise protocol. Body mass and body composition was also evaluated during the same time span. Blood samples were drawn at rest before the Wingate test for the assessment of IGF-1, hGH, LA and CrN concentration, as well as creatine kinase (CK) and lactate dehydrogenase (LDH) activities. Supplementation with alkaline creatine, combined with a progressive resistance training program, did not significantly influence (ANOVA) the level of RMP (p=0.49), RPP (p=0.31), TRPP (p=0.51), and RTW (p=0.58) in untrained male subjects. In the supplemental group, there was a significant decrease (p<0.01) in TRPP following creatine supplementation and training, yet these values were not significantly different from the control group. The supplementation and training protocol did not influence significantly body mass (p=0.68), yet post hoc analysis indicate a significant increase in body mass (p<0.001) only in group S. The applied supplementation and training protocol did not influence (ANOVA) the concentration of serum CrN (p=0.81), hGH) (p=0.26), CK (p=0.49) and LDH (p=0.64) activities. No significant changes were observed in resting blood LA concentrations of the tested subjects. It can be concluded that the ergogenic effect of creatine intake and resistance training was maintained for a week after terminating supplementation and exercise. During the next 2 weeks de-adaptation occurred and most indices of anaerobic power returned to initial values.
- alkaline creatine
- resistance training
- anaerobic power
- Open Access
Factors Determining Participation in Leisure Time Physical Activity among Former Athletes and Male non Athletes
Page range: 111 - 120
The aim of the study was to compare the impact of socioeconomic factors and self-rated health on participation in leisure time physical activity (LTPA) among former athletes and male non athletes. In the spring-summer of 1997 - 2002, two groups of males between the ages of 18 - 51 years were enrolled in the study: former athletes (n=175) and men without any (past or present) competitive sports experience (n=197). Sample selection was deliberate according to the "easy access" criterion. An anonymous, postal self-return survey included questions concerning the variables of frequency, time spent on LTPA and form of participation in LTPA, socioeconomic variables (age, marital status, residence, educational level, occupation, income level) and selfrated health (categories: very good, good, moderate, poor and very poor). Statistical analysis of the study included test of differences between two structural components and X2 test. In both groups, poor participation in LTPA was significantly associated with a negative self-rated health and low socioeconomic status (blue-collar work or unemployment, low income, low educational level), and in the group of men without any competitive sports experience, also with the age range of 35 - 51 years, and residence in a rural area. Furthermore, the impact of poor socioeconomic status on participation of men in LTPA was found to be weaker among former athletes than in men without any past competitive sports experience. The results of the study indicate that the following are necessary to improve participation of men in LTPA: propagation of competitive sports among boys and young men, and elimination of socioeconomic barriers for their physical activity.
- leisure time physical activity
- former athletes
- socioeconomic status
- self-rated health
- Open Access
Adolescent Attitudes towards Sport Depending on School Level, Gender and School Sports Club Membership
Page range: 121 - 130
The aim of the study was to evaluate adolescent attitudes towards different aspects of sport activities, in relation to school level, gender and membership in a school sports club (SSC).
The Diagnostic Questionnaire for Testing Youth's Attitude towards Physical Education and Sport developed by Strzyżewski (1990) constituted the main research tool. The present paper analyzed responses to 11 selected questions, which reflect attitudes towards sport. Three aspects were studied (1) attitude towards sport as a social phenomenon, (2) attitude towards own participation in sports activities, and (3) attitude towards school sport. The survey was launched in 623 clubs, which were randomly selected from the database of the Polish Ministry of Sport. A total of 2704 correctly filled-in questionnaires were subjected to statistical analysis.
Respondents demonstrated positive attitudes towards all three variables of interest. Non-SSC pupils/students were not different towards sport. Such situations were observed among girls from all school levels and only in a small part of the boys. However, based on the obtained results, it can be concluded that school level does not cause significant differences in adolescent attitudes towards sport (p=0.36). The attitudes are influenced by gender (attitude towards own participation in sports activities and attitude towards school sport - p<0.001) and participation in sports club activities (attitude towards sport as a social phenomenon, attitude towards own participation in sports activities, and attitude towards school sport - p<0.001).
- sport attitudes
- Open Access
Page range: 131 - 138
Developing the awareness of one's level of physical activity is an important prerequisite to change one's lifestyle into a more physically active and healthy style of living. The aim of the study is to verify the efficacy of pedometers in educational environments and to specify the differences between physical activity in boys and girls aged 17. Twenty seven boys and thirty seven girls from randomly selected classes in two high schools in Katowice, Poland participated in the study. Students wore Yamax SW-700 pedometers for three weeks, continuously recorded data from the pedometers, and used the motivational feedback booklets. The three-week intervention using pedometers was complemented with the IPAQ questionnaire to assess their physical activity during the last seven days.
For statistical analysis, we used basic statistical characteristics, Mann-Whitney test, repeated ANOVA, "effect size" coefficient ω2 (Tolson, 1980), and other partial analysis programs in Statistica 6 and SPSS 15.
Both boys and girls were less physically active on weekend days during the analyzed period. The use of pedometers did not decrease the difference between physical activity on school days and weekend days. No significant differences were found in the average number of steps per day between boys and girls, as well as no significant differences were identified in the interaction of gender vs. school and weekend days.
Additional study is necessary to confirm whether the use of pedometers in physical education classes can help decrease the differences in physical activity between boys and girls.
- physical activity
- active lifestyle