Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “work intensity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1991

Heart rate recovery from 1 minute of exercise in children and adults.

Previous studies demonstrated that the time required for oxygen uptake, CO2 production, and minute ventilation to return to baseline levels after 1-min bursts of exercise is different in children compared with adults. To test the hypothesis that the heart rate (HR) recovery time after exercise is also different in children compared with adults, we examined HR in 10 children (range 7-11 y old) and 12 adults (26-42 y old) for 10 min after 1 min of cycle ergometer exercise. Each subject exercised at work rates corresponding to 80% of the lactate or anaerobic threshold (AT), 50% of the difference between AT and maximal O2 uptake (delta), 100% of maximal uptake, and 125% of maximal uptake. Gas exchange was measured breath by breath. In adults, the HR recovery time increased significantly with work intensity as judged by the time constant of a single exponential curve fit to postburst-exercise HR [23 +/- 8 (SD) s at 80% AT, 55 +/- 16 at 50% delta, 74 +/- 13 at 100% of maximal uptake, and 83 +/- 20 at 125% of maximal uptake]. HR recovery time tended to increase with work intensity in children (16 +/- 7, 20 +/- 4, 23 +/- 7, and 27 +/- 9; for 80% AT, 50% delta, 100% of maximal uptake, and 125% of maximal uptake respectively), but to a much smaller extent, and the HR recovery time was significantly smaller in children in the high-intensity (above AT) range of exercise (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Plasma atrial natriuretic peptide in standardbred and Finnhorse trotters during and after exercise.

To study the exercise-induced changes in atrial natriuretic peptide (ANP), a hormone with cardiovascular and renal effects, an incremental submaximal exercise test on a high-speed treadmill was carried out with Standardbred and Finnhorse trotters, the former bred for speed and the latter originally for heavy work. Standardbreds performed the 2 min exercise intervals at speeds of 6, 7, 8, 9 m s-1 and Finnhorses, according to their training status, at 5, 6, 7, 8 m s-1, 4, 5, 6, 7 m s-1 or 5, 6, 7 m s-1. Steady-state heart rate (HR) was reached within each 2 min interval. The increase in HR was linear and proportional to work intensity and physical condition and it peaked, average 204 beats min-1, during the last speed of the treadmill. Plasma ANP increased significantly and equally, by 27 +/- 4 pg mL-1, in both breeds and peaked at 5 min post-exercise. The rise in ANP during exercise showed good linearity with HR and increasing work intensity. The decrease of ANP after exercise was slow, which may be connected to the regulation of water and electrolytes. Interbreed differences in plasma ANP were not observed. The results suggest a role of ANP in cardiovascular control and fluid balance during and after exercise. In addition to other possible releasing factors during exercise, the increase in HR explains about 40% of the variability in the plasma ANP values.

Age Factors↗
PubMed2005

Effect of contractile duration on intracellular PO2 kinetics in Xenopus single skeletal myocytes.

It has been suggested that skeletal muscle O(2) uptake (Vo(2)) kinetics follow a first-order control model. Consistent with that, Vo(2) should show both 1) similar onset kinetics and 2) an on-off symmetry across submaximal work intensities regardless of the metabolic perturbation. To date, consensus on this issue has not been reached in whole body studies due to numerous confounding factors associated with O(2) availability and fiber-type recruitment. To test whether single myocytes demonstrate similar intracellular Po(2) (Pi(O(2))) on- and off-transient kinetics at varying work intensities, we studied Xenopus laevis single myocyte (n = 8) Pi(O(2)) via phosphorescence quenching during two bouts of electrically induced isometric muscle contractions of 200 (low)- and 400 (high)-ms contraction duration (1 contraction every 4 s, 15 min between trials, order randomized). The fall in Pi(O(2)), which is inversely proportional to the net increase in Vo(2), was significantly greater (P < 0.05) during the high (24.1 +/- 3.2 Torr) vs. low (17.4 +/- 1.6 Torr) contraction bout. However, the mean response time (MRT; time to 63% of the overall change) for the fall in Pi(O(2)) from resting baseline to end contractions was not different (high, 77.8 +/- 11.5 vs. low, 76.1 +/- 13.6 s; P > 0.05) between trials. The initial rate of change at contraction onset, defined as DeltaPi(O(2))/MRT, was significantly greater (P < 0.05) in high compared with low. Pi(O(2)) off-transient MRT from the end of the contraction bout to initial baseline was unchanged (high, 83.3 +/- 18.3 vs. low, 80.4 +/- 21.6 s; P > 0.05) between high and low trials. These data revealed that Pi(O(2)) dynamics in frog isolated skeletal myocytes were invariant despite differing contraction durations and, by inference, metabolic demands. Thus these findings demonstrate that mitochondria can respond more rapidly at the initial onset of contractions when challenged with an augmented metabolic stimulus in accordance with an apparent first-order rate law.

Animals↗
PubMed1986

Cardiac responses to exercise in the dog before and after destruction of the sinoatrial node.

Chronotropic and dromotropic responses to treadmill exercise were compared in conscious dogs prior to and following excision of the sinoatrial node (SAN). The initial junctional rhythm accompanying removal of the SAN region was replaced within hours to days by subsidiary atrial pacemaker (SAP) foci located in the inferior right atrium along the sulcus terminalis. With SAN intact, cardiac acceleration was immediate at onset of exercise and the tachycardia was directly proportional to work intensity. Atrioventricular (AV) conduction concurrently accelerated during exercise as manifest by shortening in P-R and atrioventricular (A-V) intervals. Following SAN excision, subsidiary atrial pacemaker foci likewise demonstrated prompt tachycardias during exercise, although heart rate was significantly reduced at rest and during steady state exercise. In the SAP state, tachycardia during exercise was related to work intensity and was mediated by changes in cardiac autonomic nerve activity. Combined propranolol-atropine blockade increased heart rate at rest in the SAP state, and significantly attenuated the tachycardia accompanying treadmill exercise. Following SAN excision the P-R (A-V) interval was significantly reduced in the resting animal. In response to exercise, AV conduction time decreased in the SAP state, though the absolute levels during steady state exercise were not significantly different from prior control runs with SAN intact. Blood pressure response to exercise was similar during both SAN and SAP states. We conclude that following an initial unstable period, SAP foci maintain adequate heart rate increases in response to dynamic exercise, primarily mediated via autonomic nerve regulation.

Adrenergic beta-Antagonists↗
PubMed2005

Physiological role of carnosine in contracting muscle.

High-intensity exercise leads to reductions in muscle substrates (ATP, PCr6, and glycogen) and a subsequent accumulation of metabolites (ADP, P, H(+), and Mg(+)) with a possible increase in free radical production. These factors independently and collectively have deleterious effects on muscle, with significant repercussions on high-intensity performance or training sessions. The effect of carnosine on overcoming muscle fatigue appears to be related to its ability to buffer the increased H(+) concentration following high-intensity work. Carnosine, however, has other roles such as an antioxidant, a metal chelator, a Ca(2+) and enzyme regulator, an inhibitor of protein glycosylation and protein-protein cross-linking. To date7comma; only 1 study has investigated the effects of carnosine supplementation (not in pure form) on exercise performance in human subjects and found no improvement in repetitive high-intensity work. Much data has come from in vitro work on animal skeletal muscle fibers or other components of muscle contractile mechanisms. Thus further research needs to be carried out on humans to provide additional understanding on the effects of carnosine in vivo.

Acid-Base Equilibrium↗
PubMed1985

Noninvasive determination of the anaerobic threshold in canoeing, cross-country skiing, cycling, roller, and ice-skating, rowing, and walking.

The relationship between velocity (V) and heart rate (HR) was determined in four canoeists, 42 cross-country skiers, 73 cyclists, nine ice-skaters, 10 roller-skaters, 32 rowers, and 20 walkers. The athletes were asked to increase their work intensity progressively, from low to submaximal velocities; HRs were determined by ECG in roller-, ice-skating, and walking, or read on a cardiofrequency meter in canoeing, cross-country skiing, cycling, and rowing. In all the athletes examined the linearity of the V-HR relationship was maintained up to a submaximal speed (deflection velocity, Vd), beyond which the increase in work intensity exceeded the increase in HR. Vd and anaerobic threshold (AT), determined through blood lactate measurements, were coincident in 19 athletes (6 cross-country skiers, 3 cyclists, 2 roller-skaters, 3 rowers, and 5 walkers). Vd was correlated with the average speeds maintained in walking (20 km, n = 13, r = 0.88), cross-country skiing (15 km, n = 20, r = 0.80; 30 km, n = 8, r = 0.82; 12 km, n = 7, r = 0.86; 11 km, n = 7, r = 0.86) and cycling (1,000 m flying-start, n = 68, r = 0.83), thus showing that AT is a limiting factor in these aerobic events.

Adolescent↗
PubMed1976

The reproducibility of submaximal work heart rates-an interim report.

Work heart rates were taken from four subjects performing standardized bouts of work on the Monark Ergometer. Whilst a linear relationship was observed between heart rate and work intensity on any one day, it is evident that day to day variations in the position (intercept) of these lines exists. The slopes are virtually identical for all subjects and for different days, however the position of the lines differs widely both between and within subjects. The best linear regression equation developed for the prediction of heart rate after 180 seconds of work from pre-exercise heart rate and work intensity was found to have 95% confidence limits of +/- 12.7 beats. Heart rates are reproducible 95% of the time to within +/- 12.2 beats when pre-exercise heart rate is ignored.

Heart Rate↗
PubMed2001

Aerobic endurance training improves soccer performance.

PURPOSE: The aim of the present study was to study the effects of aerobic training on performance during soccer match and soccer specific tests. METHODS: Nineteen male elite junior soccer players, age 18.1 +/- 0.8 yr, randomly assigned to the training group (N = 9) and the control group (N = 10) participated in the study. The specific aerobic training consisted of interval training, four times 4 min at 90-95% of maximal heart rate, with a 3-min jog in between, twice per week for 8 wk. Players were monitored by video during two matches, one before and one after training. RESULTS: In the training group: a) maximal oxygen uptake (VO2max) increased from 58.1 +/- 4.5 mL x kg(-1) x min(-1) to 64.3 +/- 3.9 mL x kg(-1) x min(-1) (P < 0.01); b) lactate threshold improved from 47.8 +/- 5.3 mL x kg(-1) x min(-1) to 55.4 +/- 4.1 mL x kg(-1) x min(-1) (P < 0.01); c) running economy was also improved by 6.7% (P < 0.05); d) distance covered during a match increased by 20% in the training group (P < 0.01); e) number of sprints increased by 100% (P < 0.01); f) number of involvements with the ball increased by 24% (P < 0.05); g) the average work intensity during a soccer match, measured as percent of maximal heart rate, was enhanced from 82.7 +/- 3.4% to 85.6 +/- 3.1% (P < 0.05); and h) no changes were found in maximal vertical jumping height, strength, speed, kicking velocity, kicking precision, or quality of passes after the training period. The control group showed no changes in any of the tested parameters. CONCLUSION: Enhanced aerobic endurance in soccer players improved soccer performance by increasing the distance covered, enhancing work intensity, and increasing the number of sprints and involvements with the ball during a match.

Acceleration↗
PubMed2002

Prevalence and risk factors of occupational asthma among hairdressers in Turkey.

This study was designed to evaluate the questionnaire-based prevalence and possible risk factors of occupational asthma among hairdressers in Turkey. We investigated occupational history and respiratory, ocular, dermal, and nasal symptoms using a standardized questionnaire, evaluated worksite pulmonary function tests, and performed allergen skin testing. We then determined asthma risk factors using age- and gender-adjusted logistic regression models. The prevalence of occupational asthma in hairdressers was 14.6%. The odds ratio for hairdressers in a high work intensity group was 3.6 (95% confidence interval, 1.2 to 10.9) with a significant dose-response trend (chi 2 trend = 4.875; P = 0.027). The odds ratio for occupational asthma among workers with atopy was 4.5 (95% confidence interval, 1.2 to 17.2). We also observed an excess risk of occupational asthma with allergic rhinitis and conjunctivitis. Occupational asthma did not differ among subgroups of hairdressers. We observed an important risk of occupational asthma among hairdressers. The most prominent risk factors were work intensity and atopy.

Adolescent↗
PubMed1988

The leucocytosis of exercise. A review and model.

Exercise is known to induce an immediate leucocytosis, the magnitude of which is related, in most instances, to the intensity and duration of the work. On finishing exercise, however, the leucocyte count may change in any one of several different ways. The pattern of postexercise changes in the leucocyte count is determined mainly by the time which has elapsed since beginning exercise, rather than the work intensity or the total work done, if, for example, exercise has been intermittent. Consideration of, firstly, the circumstances under which the plasma concentrations of catecholamines and cortisol have been found separately to correlate with the leucocyte count at the finish of exercise, and, secondly, the effects on the leucocyte count of exogenous administration of these substances has led us to develop a model which can satisfactorily account for all of the principal changes in the leucocyte count that have been noted during and after exercise. It is proposed that catecholamines produced during exercise act to increase the ratio of circulating to non-circulating leucocytes, while cortisol acts, by a mechanism which involves a time lag, to increase the total number of leucocytes in the vascular compartment. Examination of previously published reports shows that many contain results which support this model. Using the model as a basis, some predictions are made that can be tested experimentally, and some experiments are suggested which should help elucidate the mode of action of catecholamines and cortisol.

Adolescent↗
PubMed1989

Adaptation of the "Conconi test" to children and adolescents.

A field test for the determination of anaerobic threshold (AT) based on the relationship between work intensity and heart rate was previously developed in adult runners (4) and then applied in various sports activities (3, 5, 9). In the current study the same relationship between running speed (S) and heart rate (HR) was determined in 274 healthy children and adolescents (169 males and 105 females). All tests were performed either outdoors on a 400-m track (n = 159, 110 males and 49 females) or indoors in a gymnasium (n = 115, 59 males and 56 females). The subjects increased their work intensity progressively from low to submaximal speeds. HR was determined by a heart rate monitor (Sport Tester TM PE 3000, Polar Electro, Kempele, Finland). In every subject examined, the linearity of the S-HR relationship was lost at a speed, called deflection speed (Sd), above which the increase in S exceeded the increase in HR. HR at Sd was defined as HRd. The respective test-retest correlation coefficients for Sd, HRd, and slope of the linear part of the graph were 0.990, 0.824, and 0.953 when determined outdoors and 0.996, 0.840, and 0.932 when determined indoors. The outdoor-indoor correlation coefficients were 0.934, 0.855, and 0.282, respectively, for Sd, HRd, and slope. The results suggest that application of this test to children and adolescents in running may prove useful in cross-sectional and longitudinal studies of the development of aerobic power during growth.

Adolescent↗
PubMed2003

Delay of muscle vasodilation to changes in work rate (treadmill grade) during locomotion.

Previous studies examining the delay to the onset of vasodilation have primarily focused on the onset of exercise, a setting complicated by the fact that the muscle pump and the vasodilator systems are both activated, making it difficult to attribute changes in blood flow to one or both. The goal here was to determine the delay to the onset of vasodilation after changes in work rate imposed by changes in treadmill grade (work intensity) during locomotion at a steady speed. The rationale was that constant speed would help ensure constant muscle pump activity (contraction frequency) such that vasodilator responses could be examined in isolation. Seven Sprague-Dawley rats underwent three trials each in which treadmill incline was suddenly ( approximately 1 s) elevated from -10 degrees to +10 degrees. The delay to the onset of vasodilation averaged 5.0 +/- 1.8 s, and this delay was not altered by inhibition of nitric oxide synthase. Similar or longer delays were seen during sinusoidal exercise. Thus there is a significant delay before the onset of vasodilation after an increase in work intensity (muscle force) during locomotory exercise at constant speed.

Animals↗
PubMed2000

Time and motion analysis of the AFL field umpire. Australian Football League.

The purpose of the present study was to quantify the movement patterns and work intensities of field umpires while officiating in the three-umpire system of the Australian Football League (AFL). Five umpires were randomly selected and videoed throughout five AFL-matches played at the Brisbane Cricket Ground. Each video was analysed manually for time spent in each of four movement modalities: forward, backward, sideways and stationary which were further analysed into the categories of forward sprinting, forward cruising/jogging and forward walking; backward fast/moderate and backward slow; sideways movement and stationary. The following calculations were made: a) the total time spent performing each movement modality; b) the relative contribution (%) of time spent in each activity; and c) the work to rest ratio. The relative time contribution of each movement modality was: Sprinting (1.9+/-0.2%), Cruising/Jogging (26.1+/-3.2%), Walking (21.9+/-3.1%). Fast/Moderate Backward (14.6+/-1.2%), Slow Backward (13.6+/-1.0%), Sideways (2.2+/-0.3%) and Stationary (19.7+/-2.7%). The average time of effort for each movement modality were found to be: Sprinting (2.2+/-0.4 secs), Cruising/Jogging (6.09+/-1.3 secs), Walking (9.9+/-1.1 secs), Backward Fast/Moderate (4.4+/-0.3 secs), Backward Slow (5.2+/-0.8 secs), Sideways (1.7+/-0.1 secs) and Stationary (7.4+/-1.4 secs). The average work to rest ratio was approximately between 1:4-1:5. The current findings provide a detailed description of the movement patterns and work intensities of AFL field umpires which may be used in the development of training programs specific to the three-umpire system.

Adult↗
PubMed2002

In vivo quantitative near-infrared spectroscopy in skeletal muscle during incremental isometric handgrip exercise.

The aim of this study was to investigate the performance of in vivo quantitative near-infrared spectroscopy (NIRS) in skeletal muscle at various workloads. NIRS was used for the quantitative measurement of O2 consumption (mVO2) in the human flexor digitorum superficialis muscle at rest and during rhythmic isometric handgrip exercise in a broad range of work intensities (10-90% MVC=maximum voluntary contraction force). Six subjects were tested on three separate days. No significant differences were found in mVO2 measured over different days with the exception of the highest workload. The within-subject variability for each workload measured over the three measurements days ranged from 15.7 to 25.6% and did not increase at the high workloads. The mVO2 was 0.14 +/- 0.01 mlO2 min-1 100 g-1 at rest and increased roughly 19 times to 2.68 +/- 0.58 mlO2 min-1 100 g-1 at 72% MVC. These results show that local muscle oxygen consumption at rest as well as during exercise at a broad range of work intensities can be measured reliably by NIRS, applied to a uniform selected subject population. This is of great importance as direct local measurement of mVO2 during exercise is not possible with the conventional techniques. The method is robust enough to measure over separate days and at various workloads and can therefore contribute to a better understanding of human physiology in both the normal and pathological state of the muscle.

Adult↗
PubMed2006

Maximal lipidic power in high competitive level triathletes and cyclists.

OBJECTIVE: To describe the fat-oxidation rate in triathlon and different modalities of endurance cycling. METHODS: 34 endurance athletes (15 male triathletes, 4 female triathletes, 11 road cyclists and 4 male mountain bikers) underwent a progressive cycloergometer test until exhaustion. Relative work intensity (VO(2max)), minimal lactate concentration (La(-)(min)), lactic threshold, individual lactic threshold (ILT), maximal fat-oxidation rate (Fat(max), Fat(max) zone) and minimal fat-oxidation rate (Fat(min)) were determined in each of the groups and were compared by means of one-way analysis of variance. RESULTS: No significant differences were found for Fat(max), Fat(min) or for the Fat(max) zone expressed as fat oxidation rate (g/min). Intensities -20%, -10% and -5% Fat(max) were significantly lower for mountain bikers with respect to road cyclists and female triathletes, expressed as % VO(2max). Intensities 20%, 10% and 5% Fat(max) were significantly lower for mountain bikers with respect to male triathletes and female triathletes, and for male triathletes in comparison with female triathletes, expressed as % VO(2max). Lactic threshold and La(-)(min) did not show significant differences with respect to Fat(max). Lactic threshold was found at the same VO(2max) with respect to the higher part of the Fat(max) zone, and La(-)(min) at the same VO(2max) with respect to the lower part of the Fat(max) zone. CONCLUSIONS: The VO(2max) of Fat(max) and the Fat(max) zone may explain the different endurance adaptations of the athletes according to their sporting discipline. Lactic threshold and La(-)(min) were found at different relative work intensities with respect to those of Fat(max) even though they belonged to the Fat(max) zone.

Adult↗
PubMed2003

Oxygen saturation response to exercise VO2 at 2100 m and 4350 m in women mountaineering trainees.

Human work performances decreases at high altitude (HA). This decrement does not appear to be similar for every individual, may be due to variety of factors like elevation, mode of induction, work intensity, physical condition and specificity of the subjects. The purpose of the study was to evaluate the effects of alteration in responses of oxygen saturation (SaO2) and oxygen consumption (VO2) to a standard exercise in women mountaineering trainees under hypobaric hypoxia. Experiments were conducted in 2 groups (10 each) of females and compared the difference in responses of native women of moderate altitude with those of the plains/low altitude. A standard exercise test (Modified Harvard Step-Test for women) was performed on a 30 cm stool with 24 cycles/min for 5 min, initially at 2100 m and then at 4350 m. The exercise VO2 values for plains dwelling women achieved apparently VO2max level at both altitude locations with significant reduction in SaO2 during standard exercise. Exercise VO2 values decreased on exposure to 4350 m with further reduction in SaO2. Whereas with same work intensity, under same situation the exercise VO2 values of the moderate altitude women did not appear to have reached VO2max. They also maintained comparatively higher level of SaO2. It may be concluded that hypoxic exposure along with mountaineering training, the moderate altitude women maintained a higher level of SaO2 during standard exercise at both altitude locations, compared to low altitude women who might have lost a compensatory reserve to defend the hypoxic stress to exercise. Thus, moderate altitude women are proved to be better fit for hypoxic tolerance/HA performance.

Adolescent↗
PubMed1993

Effects of cocaine on incremental treadmill exercise in horses.

Four mature horses were used to test the effects of two doses (50 and 200 mg) of intravenously administered cocaine on hemodynamics and selected indexes of performance [maximal heart rate (HRmax), treadmill velocity at HRmax, treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l, maximal mixed venous blood lactate concentration, maximal treadmill work intensity, and test duration] measured during an incremental treadmill test. Both doses of cocaine increased HRmax approximately 7% (P < 0.05). Mean arterial pressure was 30 mmHg greater (P < 0.05) during the 4- to 7-m/s steps of the exercise test in the 200-mg trial. Neither dose of cocaine had an effect on the responses to exertion of right atrial pressure, right ventricular pressure, or maximal change in right ventricular pressure over time. Maximal mixed venous blood lactate concentration increased 41% (P < 0.05) with the 50-mg dose and 75% (P < 0.05) with the 200-mg dose during exercise. Administration of cocaine resulted in decreases (P < 0.05) in the treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l from 6.9 +/- 0.5 and 6.8 +/- 0.9 m/s during the control trials to 4.4 +/- 0.1 m/s during the 200-mg cocaine trial. Cocaine did not alter maximal treadmill work intensity (P > 0.05); however, time to exhaustion increased by approximately 92 s (15%; P < 0.05) during the 200-mg trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Temperature responses of rats to treadmill exercise, and the effect of thermoregulatory capacity.

The relationship between work intensity and body temperature was investigated in the rat in an attempt to clarify whether alterations in thermoregulatory capacity can modify the rte and extent of body warming during exercise. Repeated noradrenaline injections led to increased hyperthermic response to that amine. However, during exercise these animals did not attain higher colonic temperatures as did the animals avoiding noradrenaline treatment. If noradrenaline was injected 60 min prior to test-exercise the body temperature of the rats rose to a higher level without the drug. The extent of this rise was, however, independent of the previous noradrenaline-treatment history. Beta blockade abolished the noradrenaline-induced hyperthermia but not the exercise-induced hyperthermia. Despite increased capacity for heat production, cold-acclimated rats did not attain higher colonic temperatures during exercise than did the running-trained, cold-stressed or sedentary control rats. However, the higher tail skin temperature of the cold-acclimated rats indicate that their heat production was enhanced but they maintained lower colonic temperature by dissipating the excess heat through the elevated blood flow to the tail and probably to other extremities. These results indicate that the rise in deep body temperature of the rats during work is proportional to work intensity and that the enhanced heat production capacity can be compensated for by increasing the heat loss activities.

Adaptation, Physiological↗