Differences between elite,junior and non-rowers in kinematic and kinetic parameters during ergometer rowing

This paper presents an analysis of the rowing parameters of differently skilled rowers. The study focuses on technique dependency on stroke rate. Five elite, five junior and five non-rowers participated, and the biomechanics of rowing on an ergometer was analyzed at stroke rates of 20, 26 and 34 str/min. The results show that elite rowers use a similar, consistent rowing technique at all stroke rates, the technique of junior rowers follows similar principles, while the technique of non-rowers varies. Elite rowers’ stroke length, handle motion and body posture do not change with stroke rate while the ratio of stroke phases, maximum forces, stroke work and joint loadings are constant at the same stroke rate but dependent on stroke rate. Junior rowers with stroke rate change also the stroke length. In non-rowers the differences can be observed in the handle motion and body posture during the stroke, their stroke length changes with stroke rate while the ratio of stroke phases stays constant. Although different movement execution is evident and variable with stroke rate, non-rowers demonstrate a consistent pattern at the same stroke rate. On the basis of the results, the crucial parameters that differentiate elite, junior, and non-rowers are identified.     

Effects of practice and preferred rate on perceived exertion,metabolic variables and movement control

One interesting feature of motor skill learning and control is our propensity to reduce the metabolic energy cost of achieving the task goal with practice and, if unconstrained, to adapt movements to task constraints using an energy-efficient preferred mode. This study investigated the effects of preferred rate and practice on metabolic variables, ratings of perceived exertion (RPE) and movement control. Six healthy well-trained male volunteers with no experience of rowing undertook one session per day over 6 days on a Concept II rowing ergometer at a power output of 100 W at preferred stroke rate (PR) and then at experimenter imposed rates of +20% (PR+) and −20% (PR−) of preferred. Heart rate and RPE declined significantly over days and there was an associated but nonsignificant reduction in oxygen consumption. Heart rate, oxygen consumption and RPE were significantly lower when rowing at preferred rate and economy was significantly greater. There was a trend toward reduced variability in the rowing cycle duration over practice days but the effect was not significant. Cycle duration was significantly less variable in the PR− phase than in the PR and PR+ phases, the latter phases were equally variable. Overall the data provide support for the view that motor learning is associated with changes to movement control parameters that reflect increased economy of energy expenditure in achieving the task goal. In addition, preferred modes (here preferred rate) appear to be associated with more economical but not more stable performances than non-preferred. PsycINFO classification: 2330; 2560; 3720     

Switching attentional focus across internal and external cues improves performance in a rowing task in novices

Performance in skill-based and endurance sports can be enhanced when an individual directs attention toward internal or external cues. However, there might be advantages in attending to specific cues at different times during a continuous sport task. The present study examined the effects of switching attention between internal and external cues when rowing. Novice rowers (N = 27) completed three 2000 m rows while focusing attention on internal cues only, external cues only, or switching between internal and external cues. Overall performance, as measured by time and power output, was best in the switching condition. Measurements of heart rate and perceived exertion were not significantly different between switching and external conditions, suggesting that these performance improvements occurred without producing significant subjective or objective physiologic change. However, a focus on external cues resulted in lower ratings of perceived exertion relative to a focus on internal cues. Self-reported motivation did not differ between conditions. Although instructions to focus internally or externally can influence performance on aerobic tasks, switching attention between these cues may enhance performance. Athletes should consider attending to various cues in rowing and, by extension, in other endurance sports.     

Content-specific activational effects of estrogen on working memory performance

The authors explored the influence of task content and the menstrual cycle phase on working memory (WM) performance. They addressed the content specificity of WM in the framework of evolutionary psychology, proposing a hormone-mediated adaptive design governing face perception. The authors tested 2 groups of healthy young women (n = 66 women with regular menstrual cycle, n = 27 oral contraceptive users) on a WM task with adult male or infant face photographs. Analyses of variance showed significant interaction between task content and estrogen level. Women were more efficient in solving the male faces task during high-estrogen phase of the cycle than during low-estrogen phase. No differences were found in the efficacy of solving the infant faces task between different phases of the cycle. Results suggest content-specific activational effects of estrogen on the WM performance and are consistent with the notion of a hormonal mechanism underlying adaptive shifts in cognition related to mating motivation.     

Specific internal and external attentional focus instructions have differential effects on rowing performance

Directing an individual to focus their attention on internal or external cues can influence performance of skill-based and endurance sports. The present study examined the effects of switching attention across different types of internal and external attentional foci in a rowing task. Novice rowers (19 male, 47 female) focussed attention on one of four different internal cues (or one of four different external cues) at discrete time points while completing a row on an ergometer. Overall, a focus on internal cues resulted in longer distance, higher power output, and higher heart rate than a focus on external cues. However, for the internal condition a focus on arm and leg muscles was associated with higher performance than a focus on breathing. For the external condition, a focus on exerting force on the handle produced higher performance than a focus on the movements of the handle or seat or on the sounds of the ergometer. Global instructions to focus internally or externally influenced performance, but the specific effects within these broad categories were also variable. The advice given to athletes and recreational exercises should consider both the broad attentional focus direction and the specific cues of the task to which attention is directed.     

Endocrine, cardiovascular, and psychological correlated of olfactory sensitivity changes during the human menstrual cycle

Signal detection measures olfactory sensitivity (d') and measures of blood pressure, heart rate, body temperature, nasal airflow, and respiration rate were repeatedly established within approximately 2.5-hr test sessions held every other day across 17 menstrual cycles of women not taking oral contraceptives, 6 menstrual cycles of women taking oral contraceptives, and 6 equivalent time periods of three men. In addition, radioimmunoassay-determined serum levels of luteinizing hormone, follicle stimulating hormone, estrone, estradiol, progesterone, and testosterone, as well as responses to the Moos Menstrual Distress Questionnaire (MDQ), were established daily or bidaily throughout the study periods. Peaks in olfactory sensitivity were noted during the second half of menses, midcycle, and midluteally in women taking and in women not taking oral contraceptives. The lack of correlation between the fluctuations in d' and the circulating hormone levels in the group using oral contraceptives suggests factors other than gonadal hormones were responsible for these changes. Significant fluctuations were also noted across the cycle phases of the normally cycling women for all the hormones examined, as well as for body temperature, nasal airflow, and the MDZ Water Retention and Pain Scales. In the oral contraceptive group, very small but statistically significant changes were observed across the cycle in body temperature and in circulating levels of luteinizing hormone and estrone. Interrelations between a number of the variables were noted both within and across the test periods in all three subject groups. The results are discussed in relation to fluctuations reported in a number of sensory systems during the menstrual cycle.     

Auditory sensitivity and tone-sequence reproduction in oral contraceptive users and nonusers

In two stages spanning a single academic year, 10 women using oral contraceptives and 11 not using oral contraceptives were tested on their auditory threshold sensitivity to six frequencies (250, 750, 1500, 3000, 6000, and 8000 Hz) as a function of phases of the menstrual cycle. 11 women (5 users and 6 nonusers) were also tested on their ability to reproduce successively longer tone sequences. Results showed that there was little variation due to phase of the menstrual cycle, with the exception that oral contraceptive users showed lower relative thresholds at low frequencies during the postmenstrual phase. Over-all, oral contraceptive users had higher absolute and relative thresholds than nonusers, except at 3000 Hz. Although not statistically significant, results on the tone-reproduction test showed an enhanced ability to reproduce tones during the premenstrual phase for women using oral contraceptives. Results are discussed in relation to previous findings.     

The Effects of Music and a Coxswain on Attentional Focus,Perceived Exertion,Motivation, and Performance During a 1,000 m Ergometer Rowing Sprint

Music has often been portrayed as a dissociative (i.e., distracting) mechanism. This study demonstrates that music may not be unifunctional in regards to attentional focus; that is, external concentration on music can coexist with task-relevant thoughts. Female intercollegiate rowers (N = 26) performed four 1,000 m sprints on a rowing ergometer at maximal effort under music, coxswain, combined music and coxswain, and control conditions. Findings indicate that during the 1,000 m rowing sprint, both external and task-relevant dimensions of attentional focus can exist simultaneously. This implies a new consideration of music as either dissociative or associative based on task-related factors.     

Quantifying continuous exercise using the ratio of work completed to endurance limit associated with exercise-induced delayed-onset muscle soreness

This study quantified training load of various exercises using a novel method developed by the authors and based on the ratio of work completed: endurance limit, associated with exercise-induced delayed-onset muscle soreness. Exercises were also quantified using the Training Impulse method. 8 runners performed a marathon and a 60-min. run at marathon velocity, and 9 rowers performed two maximal exercises (500 m and 2000 m) on a rowing ergometer. To examine the validity of the two methods, the relationships between the training loads provided by the Training Impulse and the Authors' methods, the direct comparison of the tasks performed, and the usability of the Authors' method components in regular training were assessed. Authors' method was significantly related to Training Impulse method (r = .83, p < .05) and was higher for running (r = .94, p < .05) but none was observed for rowing. In both methods, the marathon run resulted in high training load compared with the other tasks. When compared with the 60-min. run, the training load of the 2000-m row was slightly higher for the Authors' method, but lower for Training Impulse method. In the Authors' method, the delayed-onset muscle soreness component discriminates the marathon from the other tasks whereas the ration of work completed: endurance limit differentiates the 60-min. run from the 2000-m row. The duration component of the Training Impulse method could lead to overestimation of the training load of prolonged exercises compared with high intensity exercise. The relationship between the Training Impulse and the Authors' methods for prolonged exercises, the training load provided for each task, and the components of the Authors' method supported the validity of this new tool to describe exercise-induced fatigue.     

Cyclic changes in pain perception: An ROC analysis

The rating scale responses of three groups of men and women to thermal and painful radiant heat stimuli were studied over a 4-week period. Receiver operating characteristic curve parameters were computed for each of the phases of the menstrual cycle. Women with normal menstrual periods experienced a heightened sensitivity to pain during ovulation. This effect was absent in women using oral contraceptive pills and in men. The findings demonstrate that past reports of pain threshold changes in association with menstrual phase were basically sensory effects and not just a result of shifts in the observer’s criteria for reporting pain. In addition, sex differences in pain perception were found only when men were compared with women who were ovulating.     

Pendular energy transduction in the different phases of gait cycle in post-stroke subjects

MainTo analyze spatiotemporal gait parameters and the body center of mass (CoM) energy transduction at self-selected speed walking in a group of older patients with stroke.MethodsA cross-sectional study, fifteen subjects with 4.06 years post ̵stroke hemiparesis (eleven men and four women) and fifteen healthy subjects (four men and eleven women) participate in this study. Pendulum-like determining variables; Recovery (R) and Congruity percentage (%Cong) were analyzed in addition to immediate pendular re-conversion (Rint) during the phases in which the gait cycle is usually divided in clinical evaluations.ResultsHealthy subjects walked faster that stroke group (p = 0.001). %Cong was significantly higher in post-stroke respect to healthy subjects (p = 0.05). Rint showed significant differences between the groups for all phases (p = 0.05). The relation between speed and R was confirmed, for healthy (r = 0.67, p = 0.006) and post-stroke subjects (r = 0.851, p = 0.001), %Cong y Rint (r = −0.79, p = 0.001), (r = −0.93, p = 0.001) and periods of double support (r = −0.76, p = 0.001), (r = 0.69, p = 0.004) respectively.ConclusionAlteration of pendular mechanism in subjects post-stroke is associated mainly with energy transduction; mechanical energy recovered during double support phases in healthy and post-stroke subjects follows a different trend, in post-stroke subjects, a longer duration of the double support is associated with less energy loss.     

Cognitive load causes kinematic changes in both elite and non-elite rowers

The current motor literature suggests that extraneous cognitive load may affect performance and kinematics in a primary motor task. A common response to increased cognitive demand, as observed in past studies, might be to reduce movement complexity and revert to previously learned movement patterns, in line with the progression-regression hypothesis. However, according to several accounts of automaticity, motor experts should be able to cope with dual task demands without detriment to their performance and kinematics. To test this, we conducted an experiment asking elite and non-elite rowers to use a rowing ergometer under conditions of varying task load. We employed single-task conditions with low cognitive load (i.e., rowing only) and dual-task conditions with high cognitive load (i.e., rowing and solving arithmetic problems). The results of the cognitive load manipulations were mostly in line with our hypotheses. Overall, participants reduced movement complexity, for example by reverting towards tighter coupling of kinematic events, in their dual-task performance as compared to single-task performance. The between-group kinematic differences were less clear. In contradiction to our hypotheses, we found no significant interaction between skill level and cognitive load, suggesting that the rowers' kinematics were affected by cognitive load irrespective of skill level. Overall, our findings contradict several past findings and automaticity theories, and suggest that attentional resources are required for optimal sports performance.     

Hostility,oral contraceptive use,and cardiovascular reactivity in women

Abstract

Hostility, task instructions, social desirability and cardiovascular reactivity were investigated in a exploratory study of 70 female college students and employees. Women were administered the Videotaped Clinical Interview (VC1), the Marlowe-Crowne Social Desirability Scale (MC), the Cook-Medley Hostility Scale (CM), the Buss-Durkee Hostility Index (BD) and the Personal Attributes Questionnaire (PAQ) before undergoing a stressful discussion. Oral contraceptive users had significantly higher DBP at baseline. Based on PAQ scores, women were given instructions for the discussion task consistent or inconsistent with their gender-relevant styles. Instruction type predicted heart rate changes, and interacted with hostility to predict DBP reactivity. Interview-based hostility (VCI-H) was associated with increased DBP during the discussion task, as was being high hostile (low MC/high VCI-H). The CM and the BD had less association with heart rate and blood pressure changes. Oral contraceptive (OC) use was associated with higher SBP reactivity under stress, with highest SBP increases in the OC users concerned with social desirability. The complex interaction between trait dimensions like hostility, social desirability, and oral contraceptive use requires further investigation.     

Relations among heavy training stress,mood state,and performance for male junior rowers

This study investigated the influence of rapidly increased training volume on performance and recovery-stress state perceived by 10 male junior rowers. The training during the 6-day period amounted to 21.5 +/- 2.2 hr., which was equivalent to an average increase in training load by approximately 100% compared to their average training volume during the previous 4 wk. The time to row 2,000 m on a rowing ergometer and resting cortisol level were significantly increased after the 6-day training period. Scores on subscales of the Recovery Stress Questionnaire for Athletes significantly increased for somatic component of stress (Fatigue) and decreased factor indicating recovery (Social Relaxation) after the heavy training period. A correlation of .63 was found between increased training volume and scores on the Conflicts/Pressure subscale at the end of the heavy training period. Correlations were also found between changes in training volume with changes on subscales of Sleep Quality (r=-.64) and Burnout/Personal Accomplishment (r=-.66). Changes in resting cortisol levels as a result of heavy training stress were related to the changes in the following stress subscales: Social Stress (r=.76), Fatigue (r=.64), Disturbed Breaks (r=.65), and Fitness/Injury (r=.67). Changes in performance, perceived recovery-stress state and resting plasma cortisol level reflect increased stress due to high training. These results suggest that the Recovery Stress Questionnaire for Athletes could be used to evaluate the effects of rapidly increased training volume for male junior rowers.     

Pain perception to the cold pressor test during the menstrual cycle in relation to estrogen levels and a comparison with men.

Animal and human research has shown that pain sensitivity changes during the menstrual cycle. This has sometimes been ascribed to hormonal variations. The aim of the present study was to examine how perception of pain, induced by the cold pressor test to the dominant hand, was related to gender and phases of the menstrual cycle. A repeated-measures design was used, where twenty-two female students participated at two different phases of the menstrual cycle (days 2-4 and days 20-24). A control group of nineteen male students participated on two occasions, separated by a three week period. The cycle phase during which each woman began her participation was randomized. Pain was induced using the cold pressor test. Pain threshold was determined as the duration of time between when the subject first reported pain and exposure to the painful stimulus. Pain tolerance was determined as the duration of time until the subject withdraw her/his hand from the test water because the pain was too intensive. The results showed that men tolerated significantly greater pain than women. Women's pain threshold was significantly higher during the second phase of the menstrual cycle. Systolic pressure was higher in men than women, increasing more in men in response to cold pressor testing than women. Further research, including measurements of plasma hormone levels during the menstrual cycle, is needed to clarify the role played by estrogens in pain perception.     

Attention allocation under varied workload and effort perception in rowers

ObjectivesTenenbaum's effort-related model has proposed that as physical workload increases, attention allocation shifts from dissociation to association. Owing to equivocal research results regarding gender and experience differences in attention and perceived exertion reports, this study was designed to examine whether attention allocation varied as a function of perceived effort manipulated by physical workload, and whether gender and experience differences would emerge in regards to attention use.DesignA within-subjects study design was employed using measures of attention, perceived exertion, heart rate, and power output.MethodsSixty high school and collegiate rowers were recruited, and were divided into 30 experienced (15 men and 15 women) and 30 novice rowers (15 men and 15 women). After establishing a maximal power output value for each rower using the rowing ergometer, participants were asked to row at 30%, 50%, and 75% relative workload intensities for 10 min in a counterbalanced order. At each minute, measures of heart rate, attention, and perceived exertion were taken. Participants also recorded their thoughts during the session after each task.ResultsResults demonstrated that attention significantly (p<.01) shifted from dissociation to association as workload increased. The workload increase also resulted in elevated perceived exertion and heart rate. Similarly, thought classifications validated attention shift as workload increased. Experience and gender were not found to be discriminatory factors for attention allocation.ConclusionsAttention shifted from dissociation to association as workload increased; as environmental demands increase, physiological sensations dominate the individual's attention. Attention is forced to shift internally and narrow (i.e., associative) to adapt to these demands. During low or moderate workload, attention can be more flexible and voluntarily shift between associative and dissociative modes because the task demands are not overwhelming.     

Pain perception to the cold pressor test during the menstrual cycle in relation to estrogen levels and a comparison with men

Animal and human research has shown that pain sensitivity changes during the menstrual cycle. This has sometimes been ascribed to hormonal variations. The aim of the present study was to examine how perception of pain, induced by the cold pressor test to the dominant hand, was related to gender and phases of the menstrual cycle. A repeated-meausres design was used, where twenty-two female students participated at two different phases of the menstrual cycle (days 2–4 and days 20–24). A control group of nineteen male students participated on two occasions, separated by a three week period. The cycle phase during which each woman began her participation was randomized. Pain was induced using the cold pressor test. Pain threshold was determined as the duration of time between when the subject first reported pain and exposure to the painful stimulus. Pain tolerance was determined as the duration of time until the subject withdraw her/his hand from the test water because the pain was too intensive. The results showed that men tolerated significantly greater pain than women. Women’s pain threshold was significantly higher during the second phase of the menstrual cycle. Systolic pressure was higher in men than women, increasing more in men in response to cold pressor testing than women. Further research, including measurments of plasma hormone levels during the menstrual cycle, is needed to clarify the role played by estrogens in pain perception.     

Exercise adherence or maintenance among older adults: 1-year follow-up study.

Follow-up evaluation was conducted of 101 older men and women (mean age = 67 +/- 5 years) who had participated in a randomized study of physiological and psychological effects of aerobic exercise. Eighty-five subjects completed the follow-up evaluation, and almost all of them (94%) reported continuing with physical activity, as assessed by a self-report measure. Total energy expenditure was calculated as an indicator of exercise maintenance, and energy expenditure at follow-up was predicted from measures of physiological functioning, psychological well-being, and cognitive functioning obtained at the conclusion of the structured exercise program. Greater cardiorespiratory endurance, faster psychomotor speed, and lower anxiety predicted exercise behavior at follow-up, accounting for 13% of the variance in exercise behavior. Gender was not a significant predictor of exercise behavior.     

Exertion–Attention–Flow Linkage Under Different Workloads

This study explored a proposed conceptual scheme examining the relationship between perceived exertion, flow, and the attention strategies of association and dissociation. After establishing a maximal baseline, 60 rowers performed at 30%, 50%, and 75% of maximal workloads for 10 min on a rowing ergometer. Results revealed that as workload increased, attention shifted from dissociation to association. Flow also showed a change in endorsement of the 9 dimensions. We found a main effect for gender, but not for experience. Women exhibited higher global flow than did men during the 75% and maximal sessions. Results lend preliminary support for the proposed conceptual scheme in which perceived effort affects attention focus and flow experience. Applied recommendations for coaches and athletes are presented.     

神经质程度和月经周期对女性主观情绪和生理反应的影响

分别选取两组神经质程度高、低女性16名和25名, 考察两组被试在月经周期不同阶段(经期、卵泡晚期、黄体中晚期)的激素(雌二醇、孕酮)波动以及观看情绪视频(中性、搞笑、悲伤、愤怒)的主观情绪感受和生理反应的差异。结果显示高神经质女性在月经周期中对负性情绪视频的主观情绪和生理反应变化明显, 黄体中晚期对愤怒视频主观情绪体验更低, 对悲伤视频生理反应更小, 而低神经质女性的情绪反应不受月经周期影响。研究表明高神经质女性的情绪反应更易受月经周期影响, 这可能与其对孕酮水平波动的敏感性高有关。