Low-intensity Movement Research Articles

Thermal Increasing Information for Foot Surface during Jogging

Thermography information of foot is playing very important role in body character and related products design. The purpose of this study is to investigate the distribution and change character of foot skin temperature variety during low-intensity movement. Totally 19 subjects participated in this testing, skin surface temperature monitor was using high-precision Infrared Thermal Imager. The average foot skin temperature existed a significant difference at rest condition. After 30min persistent low-intensity exercise, each area of the foot was increased, and the increasing trend was quite similar. This study could provide the basis of foot physiological function understanding.

Time-motion and heart-rate characteristics of adolescent female foil fencers

The aims of this study was to understand the time-motion and heart-rate characteristics of adolescent female foil fencing, explore the differences between the 5-touch and 15-touch bouts and compare these results with previous analysis of elite female foil fencers. Eight adolescent female foil fencers (age 14.3 ± 1.2 y, stature 157 ± 3.8 cm, body mass 45.9 ± 5.2 kg) were analysed at a youth fencing competition. Each fencer wore a heart-rate monitor throughout the competition and bouts were filmed so time-motion analysis could be carried out. Five movement classifications were used for the time-motion analysis, this were grouped into three categories based on movement intensity: Low, Moderate and High. High-intensity movement accounted for 8.8 ± 4.4 % of total bout time with a mean duration of 0.8 ± 0.2 s. A higher percentage of low-intensity movement was recorded in the 15-touch bouts, with a higher percentage of high-intensity movement recorded in the 5-touch bouts. The mean duration of low-intensity movement was longer in the 15-touch bouts compared to the 5-touch bouts and a higher mean heart-rate was recorded in the 15-touch bouts compared to the 5-touch bouts. The results from this study suggest that adolescent female foil fencers perform a greater percentage of high-intensity movement in 5-touch bouts compared to 15-touch bouts. However, these fencers demonstrate a higher heart-rate in the 15-touch bouts. The practical application of this study is that adolescent female foil fencers must have a strong aerobic base to maintain a lower heart-rate in competition and ensure that fatigue does not become a limiting factor to performance.

The orexin neuropeptide system: physical activity and hypothalamic function throughout the aging process.

There is a rising medical need for novel therapeutic targets of physical activity. Physical activity spans from spontaneous, low intensity movements to voluntary, high-intensity exercise. Regulation of spontaneous and voluntary movement is distributed over many brain areas and neural substrates, but the specific cellular and molecular mechanisms responsible for mediating overall activity levels are not well understood. The hypothalamus plays a central role in the control of physical activity, which is executed through coordination of multiple signaling systems, including the orexin neuropeptides. Orexin producing neurons integrate physiological and metabolic information to coordinate multiple behavioral states and modulate physical activity in response to the environment. This review is organized around three questions: (1) How do orexin peptides modulate physical activity? (2) What are the effects of aging and lifestyle choices on physical activity? (3) What are the effects of aging on hypothalamic function and the orexin peptides? Discussion of these questions will provide a summary of the current state of knowledge regarding hypothalamic orexin regulation of physical activity during aging and provide a platform on which to develop improved clinical outcomes in age-associated obesity and metabolic syndromes.

A time-motion analysis of elite women’s foil fencing

This study sought to carry out a comprehensive time-motion analysis of elite women’s foil fencing to understand the demands being placed on fencers in competition. A key part of this study was to identify the differences between 15-touch, 5-touch and team bouts. 100 international women’s foil fencing bouts were analysed and five movement classifications were used during the data collection, which were consolidated into three categories of varying intensities for analysis. This study found that high-intensity movements accounted for 6.2 ± 2.5% of total bout time in elite women’s foil fencing. These high-intensity movements had a mean duration of 0.7 ± 0.1 s with a mean recovery period of 10.4 ± 3.3 s. The only “large” difference between the bouts was found for the mean duration of the low-intensity movements in the 15-touch bouts. All other differences were “moderate”, “small” or “trivial”. These results suggest that similar training plans could be used to physically prepare fencers for 15-touch, 5-touch and team bouts and should consist of primarily anaerobic alactic and aerobic activities. This study has provided a basis from which further research could be carried out, while the movement classifications have a range of applications within the study of fencing.

Relationship Between Running Loads and Soft-Tissue Injury in Elite Team Sport Athletes

Although the potential link between running loads and soft-tissue injury is appealing, the evidence supporting or refuting this relationship in high-performance team sport athletes is nonexistent, with all published studies using subjective measures (e.g., ratings of perceived exertion) to quantify training loads. The purpose of this study was to investigate the risk of low-intensity (e.g., walking, jogging, total distances) and high-intensity (e.g., high acceleration and velocity efforts, repeated high-intensity exercise bouts) movement activities on lower body soft-tissue injury in elite team sport athletes. Thirty-four elite rugby league players participated in this study. Global positioning system data and the incidence of lower body soft-tissue injuries were monitored in 117 skill training sessions during the preseason and in-season periods. The frailty model (an extension of the Cox proportional regression model for recurrent events) was applied to calculate the relative risk of injury after controlling for all other training data. The risk of injury was 2.7 (95% confidence interval 1.2-6.5) times higher when very high-velocity running (i.e., sprinting) exceeded 9 m per session. Greater distances covered in mild, moderate, and maximum accelerations and low- and very low-intensity movement velocities were associated with a reduced risk of injury. These results demonstrate that greater amounts of very high-velocity running (i.e., sprinting) are associated with an increased risk of lower body soft-tissue injury, whereas distances covered at low and moderate speeds offer a protective effect against soft-tissue injury. From an injury prevention perspective, these findings provide empirical support for restricting the amount of sprinting performed in preparation for elite team sport competition. However, coaches should also consider the consequences of reducing training loads on the development of physical qualities and playing performance.

Profile of movement demands of national football players in Australia

Descriptive data on game movement demands of contemporary players in the Australian National Soccer League (NSL, now the A League) are lacking. The purpose of this study was to profile movement demands of NSL games and specifically analyse distance covered, time in various speed categories (e.g., walking, jogging, striding, etc.), number of sprint speed efforts and overall mean player speed. Video tapes of 45 players from the 2002 to 2003 NSL season were analysed for whole- and half-game movement patterns and game statistics using Trak Performance software. Bivariate and ANOVA statistics were used for between game halves and positional comparisons. Results showed no changes to the frequency and speed of high intensity demands in both halves of the game. However, a 14% slower overall speed in the second half of the game when compared with the first half was attributed to fewer observations of the low intensity movements (9.0% less walking and 12.4% less jogging) and more stationary periods. Engagement in game events such as kicking and passing was also 11.2% less frequent in the second versus first half of games. Position-specific results of higher movement speeds of midfield players (7.2kmh(-1)), compared with defenders (6.1kmh(-1)), agree with previous results from international professional leagues. The results provide position-specific directions for future conditioning drills and benchmark fitness requirements in high level soccer players. The results also highlight the challenge to ensure consistency of second-half performances for elite level soccer players in Australia.

Do correlations exist between chromatophore arrangement and photosynthetic activity in seaweeds?

In Dictyota dichotoma, as in many other plants, the chromatophores which at low intensities occupy the cell walls perpendicular to the light beam move to the side walls parallel to the light beam if exposed to high light intensities. The aim of this investigation was to find out whether or not the changes from low- to high-intensity arrangement and vice versa function as an active control mechanism to regulate photosynthetic activity in D. dichotoma under the respective light condition. Four different experimental approaches were made: (a) In white and blue light experiments the changes of the transmittance and of the rate of photosynthetic oxygen production in high- and low-intensity arrangement were compared. (b) The kinetics of the depression and recovery of the PS-rates, as well as of the transmittance changes, were determined during high- and low-intensity movement, respectively. (c) Transmittance and PS-rates of thalli under illumination with polarized and unpolarized light of the same intensity (1,000 1x) were compared. (d) PS-rates of thalli after darkening as well as after preirradiation with weak and strong red light, conditions under which the chromatophores occupy the same position in the cells, were measured. In all these experiments the photosynthetic activity was strongly influenced by pre-illumination, but was independent of the respective chromatophore arrangement. This finding was confirmed by experiments with two other algae: (1) In the brown alga Alaria esculenta which does not display light-induced chromatophore displacements and concomitant transmittance changes, pre-irradiation with high light intensities decreases the PS-rates. (2) In the green alga Ulva lactuca, which shows circadian chloroplast movements, the PS-rates depend on the pre-irradiation only, irrespective of the chloroplast position. Thus we may conclude that in these organisms the function of chromatophore displacements is not the regulation of photosynthetic activity. Other ecological functions are discussed.

Die inverse Schwachlichtbewegung des Mougeotia-Chlorophsten: Die Induzierbarkeit wird durch zeitabhängige Dunkelreaktionen des Phytochroms gehemmt

Summary The inverse low intensity movement of the Mougeotia chloroplast is a response to polarized red light (R) vibrating parallel (∥) to the long axis of the cell, whereby the chloroplast turns from face to profile position. This response requires a preexisting gradient of phytochrome Pfr produced by preirradiation with polarized red light vibrating perpendicular to the long axis of the cell (⊥). In the present study, the efficiency of the preirradiation is investigated. With increasing energy of R ⊥, the efficiency reaches a maximum and begins to decline as the irradiation time is increased beyond 1 to 3 minutes (fig. 1). This declining efficiency indicates an inhibiting effect of prolonged preirradiation. This inhibiting effect can be simulated by two short preirradiations (R ⊥), separated by a dark interval of 10 min or more (fig. 2, 3). Hence, we are dealing with a time effect rather than with an energy effect, and this time effect is started by the first of the two preirradiations (1st P). To be effective, the inhibitory 1st P needs very little energy, and reciprocity holds within the range of seconds (fig. 5). R ⊥ is more inhibitory than unpolarized R, whereas R ∥ is not inhibitory (fig. 6); instead, R ∥ given after R ⊥ cancels the inhibitory effect of R ⊥ (fig. 7). Even far-red (FR) can substitute for R as an inhibiting 1st P, with ⊥, ∥ and unpolarized FR being about equally effective (fig.8a); here again only little energy is needed and reciprocity holds (fig. 8b). Because of the similar effect of R and FR, a true R-FR antagonism cannot be found, but the last irradiation determines the effect (fig. 9). Nearly all observations point to phytochrome as the photoreceptor pigment of the 1st P. To confirm this, a quantitative comparison has been made between the induction of the normal low intensity movement in Mougeotia (profile to face movement) by R or FR and the inhibitory effect of the 1st P in the inverse low intensity movement. The increasing parts of the dose-response curves coincide fairly well (fig. 11). «Classical» time effects of phytochrome, viz. dark reversion and dark destruction, are unlikely to account for the effect reported here. Hence, a new speculation has been introduced into the Mougeotia system, based upon recent reports on phytochrome binding: Whenever a gradient of Pfr is established, this Pfr is bound, leaving behind a gradient of mainly unbound Pr. Whereas the gradient of bound Pfr should be stable, the gradient of free Pr could be expected to level in a time-dependent process, thus giving rise to completely different starting conditions for the next irradiation.

Phytochromreaktionen bei Mougeotia mit unterschiedlicher spektraler Wirkungsverteilung

Summary In the cells of the green alga Mougeotia the large flat chloroplast orients itself with respect to the incident direction of red light in two different ways. In the case of the «normal low-intensity movement», the chloroplast turns its face to the light; the response is induced by unpolarized light or by polarized light vibrating perpendicular to the long axis of the cell. In the «inverse low-intensity movement», however, the chloroplast turns its edge to the light, a response which is induced only by polarized light vibrating parallel to the long axis of the cell. Both these responses are controlled by gradients of phytochrome Pfr. The pattern of dichroic orientation is different for Pr and Pfr. This difference is assumed to modify the spectral sensitivity of the «normal» response as compared to the absorption characteristic of Pr. In contrast, no such modification is expected concerning the «inverse» response. To test this prediction, the two responses were compared using two spectral regions, i.e. red light (650 to 675 nm) and long-wavelength red light («middle red», 679 to 695 nm). Differences were found as expected (cf. fig. 3 and 4). The experiments thus confirm the model of the dichroic orientation of phytochrome and its bearing on the perception of light direction. Some additional experiments confirm the hypothesis which has been put forward to explain the «inverse low-intensity movement» (fig. 10). In Mougeotia, newly formed Pfr is more effective than «old» Pfr, whereby the ageing occurs within a period ranging in length from seconds to half a minute.

Recording microphotometer for determination of light induced chromatophore movements in brown algae

A recording microphotometer for measuring the reaction amplitude and the kinetics of light induced chromatophore movements is described. It consists essentially of a Zeiss universal microscope which is equipped with a photomultiplier to detect the transmission changes in the test object caused by the light induced chromatophore displacement. Long term experiments are enabled by setting the light program with the aid of an automated filter change. As object the brown alga Dictyota dichotoma was used. To study the object under nearly natural conditions it is incorporated into a flow-through cuvette coupled with a recycling system for nutrient medium supply and gas exchange. Long term experiments demonstrated that the test object still gave good reactions after about 1 month experimental treatment. In all experiments notable differences in the kinetics of high and low intensity movement have been observed. Intensity/reaction-amplitude experiments showed that the extreme high intensity arrangement is achieved at irradiation levels between 12,000 and 23,000 lux, whereas the extreme low intensity arrangement was found between 500 and 2000 lux, both depending on the sensitivity of the individual object investigated.

Untersuchungen zum Photoreceptorproblem beim tonischen Blaulicht-Effekt der Starklichtbewegung des Mougeotia-Chloroplasten

Summary If irradiated simultaneously from different directions with blue light of high intensity and with red light of low intensity, the chloroplasts of Mougeotia are oriented by red rather than by short wave length light. The main effect of blue light seems to be, in this case, to change the chloropla sts from a positive to a negative phototact ic response, oriented by phytochrome. Thus, the additional given blue light has a tonic effect, i. e. independent of its direction (SCHONBOHM, 1966 b, 1967 a). It seems to be possible, that the difference between the action spectra of the high intensity movement of Mougeotia-chloroplasts (SCHONBOHM, 1963) and the action spectra of chloroplast movements of other objects (HAUPT, 1963; HAUPT and SCHONBOHM, 1970) is caused by the fact that both photoperception in phytochrome and photoperception in a yellow pigment arc represented by the action spectra of chloroplast movement of Mougeotia obtained when irradiating only with a single radiation source. In the following experiments we will record action spectra for the tonic blue light effect only; we have to take care of the action-dichroism, which we have found in former investigations (SCHCNBOHM, 1968). Polarized red light vibrating perpendicularly (r ⊥ or parallel (r ∥) to the cell axis is given simultaneously with blue light (bl). The following results have been obtained in the present investigations. 1. a) The action spectrum for the tonic effect of unpolarized blue light (bl *. with r ⊥ does not differ remarkably from the action spectra for the high intensity movement induced by blue light only (ef. fig . 2 with fig. 1). b) If we compare the action spectra for the effect of unpolarized blue light (bl *. with or without r ⊥ with the action spectra for the tonic effect of polarized blue light (bl ∥. with r ⊥) in the latter we can see a pl ateau reaching from ca. 450 nm to 470 nm instead of one peak near 465 nm (fig. 4). In the latter action spectra we do not find a relativel y high peak in the near ultraviolet as we did in the former action spectra (bl *, with or without r ⊥). 2. a) It has been demonstrated that polarized blue light (λ : ca. 400-500 nm) is tonically much more effective, if vibrating parallel to the cell axis (bi ∥, with r ⊥ than if vibrating perpendicularly (bl ⊥, wirh r ⊥) (fig. 3). b) This action dichroism is inverse, if Mougeotia is irradiated with ultraviolet light (λ = 363 nm) rather than with polarized visible blue light (λ > 400 nm) (fig. 7). c) If the wavelength of the blue light is longer than 400 nm the action dichroism for the tonic blue light effect remains constant during the whole day, whereas it is changing in a diurnal rhythm in near ultraviolet light (fig. 8). d) Action dichroism for the tonic blue light effect of the high intensity movement of Mougeotia-chloroplasts cannot be caused by an action dichroism of a countercurrent «low intensity movement» which is induced simultaneously by the same intensities of polarized blue light as are needed for high intensity movement (ef. fig. 9 and 10).

Agonistic Behavior and Territory in the American Redstart

A few essential terms are reviewed. Agonistic behavior concerned with attack and escape. Individual distance is an area around a bird, which moves with it, has no topographical reference, and into which no other individual allowed to come (Conder, 1949). Displays are defined by Moynihan (1955) as those peculiarly standardized and often exaggerated performances, including all vocalizations and many movements and postures, which have become specialized and modified as social signals or releasers. Blest (1961) describes ritualization as evolutionary process responsible for the existence of interand intra-specific signalling movements. Intention movements are the incomplete and low intensity movements, so called by Heinroth because they reveal what the animal 'intending to do' . (Marler, 1956). Tendency used here in the sense of Hinde given by Marler (1956) as the readiness to show a particular type of behaviour as observed under natural conditions. The strengths of the attack and escape tendencies are determined by using the methods described by Tinbergen (1959). The first method involves recording what behavior follows a given display if the stimulus situation (i.e., the other bird) remains constant. This method requires many observations of the same display since the stimulus situation often varies in natural encounters. If a display leads to attack 70 per cent of the time and to escape 30 per cent, it can be said that this display caused by a relatively strong attack tendency in conflict with a weaker escape tendency. Another method involves an analysis of the situations in which the display occurs and frequently used in this study in combination with the first method. The least reliable method consists of analyzing the form of the display. For instance, if it consists mainly of intention movements to fly from the opponent, one can postulate that it reflects a strong escape tendency. The function of a display determined by observing the response of the other bird (Tinbergen, 1959). For example, if a certain display by one bird typically causes the second bird to flee or to cease an approach, the display has a threat function.