Inter- and Intra-Individual Variations during the Progress of Motor Learning

Abstract

The effects of practice and the passage of time on individual differences (true-score variance) and intra-individual variation were investigated. One hundred and twenty male university students were tested on a Koerth type pursuit rotor. One group was tested on six days spaced over a three-week period. Another group performed the same motor task two days only—test and retest being separated by an interval of three weeks. Each day of practice was the same for both groups—sixty 15-second trials separated by a 10-second intertrial rest. It was concluded that true-score variance as well as intra-individual variance tend to parallel the initial increases in performance and then stabilize in later practice. Since the true-score variance increased greatly as compared with intra-individual variance in early performance, the correlation between adjacent trials increased. The effect of the lay-off was to increase both individual differences and intra-individual variance to a substantial and statistically significant degree.     

Influence of Three Different Training Programs on Strength and Speed of a Limb Movement

Abstract

The experiment was designed to compare the effects of isometric-isotonic (A), dynamic-overload (B), and free swing (C) exercise programs on the speed and strength of a lateral arm movement The 26 college men in each group—three experimental and one control—were given pre- and post-training speed and strength trials. Each experimental group performed its assigned exercise twice a week during the 10-week training period. Reliability coefficients for both strength and speed of movement measurements were found to be high. Following training there were significant speed increases in both the isometric-isotonic and dynamic-overload groups (t=10.06 and 8.10; however, the difference in speed gain between conditions was nonsignificant (F=.10). Also, strength increases in both of these groups were significant (t=8.81 and 3.08), with that of the isometric-isotonic group significantly greater than the dynamic-overload group (F=5.11). No significant speed or strength gains were registered by either the free swing or control group.     

Double poling kinematic changes during the course of a long-distance race: effect of performance level

ABSTRACT

We aimed to evaluate the changes in double poling (DP) kinematics due to a long-distance cross-country skiing race in athletes with different performance levels. A total of 100 cross-country skiers, belonging to 10 different performance groups, were filmed on flat terrain 7 and 55 km after the start line, during a 58-km classical race. Cycle velocity, frequency and length decreased from the best to the lower-ranked group, while duty cycle increased (all P <.001). Between track sections, cycle velocity and length decreased, duty cycles increased (all P <.001) while frequency was unaltered (P =.782). Group*section interactions resulted for cycle velocity (P =.005). Considering all the participants together, % change in cycle velocity between sections correlated with % change in length and duty cycle (all P <.001). Thus i) skiers in better groups showed longer and more frequent cycles as well as shorter duty cycles than skiers in slower groups; ii) throughout the race all the groups maintained the same cycle frequency while decreasing cycle velocity and length; iii) better groups showed a lower reduction in cycle velocity. Individually, a low reduction in cycle velocity during the race related to the capacity to maintain long cycles and short duty cycles.     

Effect of Guided Practice on Overhand-Throw Ball Velocities of Kindergarten Children

Abstract

Forty-five children from two intact kindergartens in one school were randomly assigned by sex to (a) an experimental group which received a movement program that included 120 min of guided practice in the overhand throw; or (b) a control group which received the same movement program but no exposure to the throw. A third group (N = 24), randomly selected by sex from a comparable school, received no movement program. Before and after the eight-week instructional period, ten trials of each child's overhand throw for force were filmed. Horizontal ball velocities were simultaneously recorded. ANOVAs on pre- and posttest ball velocities for each sex within each treatment group revealed no significant practice effect over ten trials (p > .05); thus, the trial mean was used as each subject's score. Two-way ANOVAs (treatment X sex) on the pre- and posttest data indicated no significant velocity differences (p > .05) between groups either before or after instruction. Boys had significantly greater velocities than girls (p < .05). Eight weeks of instruction that included 120 min of guided practice in the overarm throw did not significantly change the ball velocities of kindergarten children when compared to two groups with no formal throwing experience.     

Physiological Correlations With Short,Medium, and Long Cycling Time-Trial Performance

Purpose: Several studies have demonstrated that physiological variables predict cycling endurance performance. However, it is still unclear whether the predictors will change over different performance durations. The aim of this study was to assess the correlations between physiological variables and cycling time trials with different durations. Methods: Twenty trained male cyclists (maximal oxygen uptake [VO₂max] = 60.5 ± 5.6 mL/kg/min) performed 4 separate experimental trials during a 2-week period. Cyclists initially completed an incremental exercise test until volitional exhaustion followed by 3 maximal cycling time trials on separate days. Each time trial consisted of 3 different durations: 5 min, 20 min, and 60 min performed in a randomized order. Results: The main results showed that the physiological measures strongly correlated with long cycling performances rather than short and medium time trials. The time-trial mean power output was moderately high to highly correlated with peak power output and VO_2max (r = .61–.87, r = .72–.89, respectively), and was moderately to highly correlated with the lactate threshold Dmax method and second ventilatory threshold (r = .52–.75, r = .55–.82, respectively). Conclusions: Therefore, trained cyclists should develop maximal aerobic power irrespective of the duration of time trial, as well as enhancements in metabolic thresholds for long-duration time trials.     

Progressive velocity throwing training increases velocity without detriment to accuracy in sub-elite cricket players: A randomized controlled trial

Abstract

Throwing performance is vital within the sport of cricket. However, little published evidence exists regarding methods to improve throwing velocity and/or accuracy in any cricket-playing population. This study, therefore, assessed the efficacy of progressive velocity throwing training on throwing velocity and accuracy in a cricket-specific test. Eighteen sub-elite male cricket players were assessed for maximal throwing velocity and throwing accuracy at four different throwing velocities relative to maximal throwing velocity. The participants were randomly assigned to either an intervention (n=9) or control (n=9) group. Both groups performed usual pre-season activities for 8 weeks, during which the intervention group performed two additional specific throwing training sessions per week. Maximal throwing velocity was re-assessed at 4 weeks and the progressive velocity throwing programme was adjusted accordingly. The 8-week progressive velocity throwing training significantly increased peak and mean maximal throwing velocity (P = 0.01). Absolute changes in peak and mean maximal throwing velocity were negatively and significantly correlated with initial maximal throwing velocity at 4 weeks (r=?0.805, P = 0.01 and r=?0.806, P = 0.01 respectively) but not at 8 weeks. No significant difference was observed in accuracy for either group at any time. This is the first published study to describe the effectiveness of a progressive velocity throwing training programme on throwing performance in a group of sub-elite cricket players. The addition of two specific throwing training sessions per week can increase maximal throwing velocity without detriment to throwing accuracy.     

Creatine Kinase Activity Weakly Correlates to Volume Completed Following Upper Body Resistance Exercise

In the current study, we examined the relationship between serum creatine kinase (CK) activity following upper body resistance exercise with a 1- or 3-min rest between sets. Twenty men performed two sessions, each consisting of four sets with a 10-repetition maximum load. The results demonstrated significantly greater volume for the 3-min condition (M = 4,156 kg, SD = 867, for 3 min; vs. M = 3,503 kg, SD = 759, for 1 min; p < .001), with no significant differences in delta CK activity between conditions (p = .574). Nevertheless, there was a weak correlation between the delta CK activity and total volume of exercise completed (r = .55 with a 1-min rest, and r =.45 with a 3-min rest). Therefore, the volume following upper body resistance exercise correlates weakly with serum CK levels, irrespective of rest interval length between sets.     

Kinematic characteristics of elite men's 50 km race walking

Abstract

Race walking is an endurance event which also requires great technical ability, particularly with respect to its two distinguishing rules. The 50 km race walk is the longest event in the athletics programme at the Olympic Games. The aims of this observational study were to identify the important kinematic variables in elite men's 50 km race walking, and to measure variation in those variables at different distances. Thirty men were analysed from video data recorded during a World Race Walking Cup competition. Video data were also recorded at four distances during the European Cup Race Walking and 12 men analysed from these data. Two camcorders (50 Hz) recorded at each race for 3D analysis. The results of this study showed that walking speed was associated with both step length (r=0.54,P=0.002) and cadence (r=0.58,P=0.001). While placing the foot further ahead of the body at heel strike was associated with greater step lengths (r=0.45,P=0.013), it was also negatively associated with cadence (r= ?0.62,P<0.001). In the World Cup, knee angles ranged between 175 and 186° at initial contact and between 180 and 195° at midstance. During the European Cup, walking speed decreased significantly (F=9.35,P=0.002), mostly due to a decrease in step length between 38.5 and 48.5 km (t=8.59,P=0.014). From this study, it would appear that the key areas a 50 km race walker must develop and coordinate are step length and cadence, although it is also important to ensure legal walking technique is maintained with the onset of fatigue.     

The relationship between mental toughness and dispositional flow

Abstract

This article tested the relationship between mental toughness (MT) and dispositional flow. A sample of 135 athletes (M age=20.81 years, SD=2.76), derived from University sports teams and local sports clubs, gave informed consent before completing questionnaires to assess MT and dispositional flow. Pearson correlations revealed a significant and positive relationship between total MT and global flow scores (r=0.65, p <0.001). Correlations between total MT and dispositional flow subscales were all found to be significant and positive, ranging from 0.26 to 0.68. Correlations between global flow and MT subscales were also all significant and positive, ranging between 0.43 and 0.65. Linear regression analyses found MT subscales to account for 45% of the variance in disposition flow, and flow subscales to account for 50% of the variance in MT. These results suggest a reciprocal relationship between MT and flow.     

Generality vs. Specificity of an Extension Power Measurement of the Arms and Legs

Abstract

To determine the relationship between the extension power of the arms and power of the legs, 26 male Macalester College students were tested on a modified Biokinetic Swim Bench. All measurements were measured accurately and reliably. Correlations between individual abilities on the leg extension and the arm extension tasks are low, r =.194. Between the right arm and the right leg the r = .041; and between the left arm and the left leg the r = .227. These correlations are not significant. It was concluded that extension power abilities are highly specific in nature and that assuming arm power from a leg power measurement is not a viable alternative to actual measurement of the arm power.     

Muscle Fiber Type Composition and Knee Extension Isometric Strength Fatigue Patterns in Power- and Endurance-Trained Males

Abstract

Muscle fiber type composition in the vastus lateralis and knee extension isometric strength fatigue patterns were assessed in eight endurance-trained and eight power-trained males. Two different 25-trial isometric contraction exercise regimens were administered: a 10-second contraction, 5-second intertrial rest condition designed to induce a fast rate of fatigue and a 10-second contraction, 20-second intertrial rest condition designed to induce a slower rate of fatigue. The power group fatigued almost four times faster than the endurance group in the 10:5 exercise condition. In the 10:20 exercise condition, the endurance group showed no fatigue pattern while the power group had a significant strength decrement of 32%. In both exercise conditions, the power group exhibited more complex fatigue patterns in terms of statistically significant trend components. Maximum isometric strength correlated positively with slow twitch (ST) percent number in power (r = .80) and endurance (r = .48) groups, but negatively with linear trend coefficients in endurance (r = -.62) and power (r = -.80) groups. Maximum isometric strength also correlated higher with fatigue curve trend coefficients than did muscle fiber type composition. Thus, a faster rate of fatigue was associated with higher maximum isometric strength and with higher ST percent number and area. Since maximum isometric strength correlated with body weight (r = .86 for groups combined), both maximum isometric strength and muscle mass appear to be more important determinants of knee extension isometric strength fatigue patterns than muscle fiber type composition.     

A New Motor Learning Task: The Foot-Twist Tracking Task

Abstract

Sixty college men were tested on a new motor learning task: the foot-twist tracking task. They were given 35 one-min. trials; each consisted of 30 sec. of work followed by 30 sec. of rest. A 5-min. rest period was interpolated between trials 25 and 26 to allow for the dissipation of reactive inhibition accrued during prerest performance. The results supported the expectation that practice on the new task would result in significant amounts of learning. However, the improvement in performance, while fairly large (21%), is substantially less than that found on the pursuit rotor and other large muscle motor coordination tasks. The expectation of reliable learning scores is also supported by the present results (r = .77). This learning reliability is relatively high when compared with those obtained on other large muscle motor learning tasks.     

Effects of tapering on physical match activities in professional soccer players

ABSTRACT

This study aimed to examine: (i) the effect of decreasing training load (TL) during taper weeks on physical match activities in professional soccer players, and (ii) to disclose the relationship between weekly TL and physical match activities. Rating of perceived exertion was collected after each training session and match to quantify the TL in 19 professional players over 17 standard and 7 taper weeks during the season. Physical match activities were quantified by a computerised match analysis system and compared between standard training and taper weeks. Compared to standard weeks, the duration and frequency of training sessions during the taper weeks decreased (?21.7% and ?18.8%, respectively; P < 0.01) with no change in intensity (?4.8%; P = 0.09). Consequently, the weekly TL decreased during the taper weeks (?25.5%; P < 0.01). Increases in distance covered by intense running (+15.1%; P < 0.05), high-intensity running (HIR) (+15.7%; P < 0.01), number of sprints (+17.8%; P < 0.05) and number of high-speed runs (+15.7%; P < 0.05) were observed during the seven matches played after the taper weeks. High relationships were observed between TL and HIR distance covered, number of HIR and number of sprints (r = ?0.53; r = ?0.55; r = ?0.65, respectively; P < 0.01). Decreasing TL during taper weeks by reducing training duration and frequency but maintaining intensity was associated with an increase in physical activities during matches. However, it needs to be determined whether tapering or other match factors led to the changes in match activity.     

The relationship between multiscale dynamics in tremulous motion of upper limb when aiming and aiming performance in different physical load conditions

ABSTRACT

The dynamics of tremulous motion in the upper limb is complex. We aimed to explore the relationship between the complexity of upper limb tremor when aiming and aiming performance and the influences of physical load on the two outcomes. Fifteen modern pentathlon athletes were recruited and completed two 1000-m treadmill running and three 60-s standard aiming task trials: one at baseline and each of the other two immediately after each running. The time series of light spot trace on the target was measured using a high-speed camera. The complexity of this time series was quantified using multiscale entropy. The effective aiming rate was used to assess the aiming performance. We observed that participants with lower tremor complexity had lower effective aiming rate across three physical load conditions (r² > 0.38, p < 0.01). Physical load decreased both tremor complexity (F = 4.8, p = 0.01) and effective aiming rate (F = 13.5, p < 0.0001), but no difference was observed after 1000-m running compared to that after 2000-m running. The per cent change of tremor complexity associated with the change of effective aiming rate (r² = 0.55, p < 0.0001). This pilot study demonstrates that multiscale complexity of tremulous motion in the upper limb when aiming may serve as a novel marker to assess the physiologic system functionality when aiming.     

Relationship between different push-off variables and start performance in experienced swimmers

Abstract

The objective of this study was to determine the relationship between different variables measured with a force plate during the swimming start push-off phase and start performance presented by times to 5, 10 and 15?m. Twenty-one women from the Slovenian national swimming team performed two different swim starts (freestyle and undulatory) on a portable force plate to a distance further than 15?m. Correlations between push-off variables and times to 5, 10 and 15?m were quantified through Pearson's product-moment correlation coefficient (r). The variables that significantly correlated (p?<?.05) to all times measured in the two starts performed were: average horizontal acceleration (freestyle: r?=??0.58 to ?0.71; and undulatory: r?=??0.55 to ?0.66), horizontal take-off velocity (freestyle: r?=??0.56 to ?0.69; and undulatory: r?=??0.53 to ?0.67) and resultant take-off velocity (freestyle: r?=??0.53 to ?0.65; and undulatory: r?=??0.52 to ?0.61). None of the variables derived from the vertical force were correlated to swimming start performance (p?>?.05). Based on the results of this study, we can conclude that horizontal take-off velocity and average horizontal acceleration (calculated as the average horizontal force divided by swimmer's body mass) are the variables most related to swimming start performance in experienced swimmers, and therefore could be the preferred measures to monitor swimmers’ efficiency during the push-off phase.     

Inter-segmental coordination in progressions for the longswing on high bar

Abstract

The aim of this study was to determine if critical parameters for elite performance could be identified among a population of female shot putters. The performance of seven of the top women shot putters competing at the 2002 USA National Championships was examined. Video data were captured using two Panasonic 60 Hz cameras and the best throws of each athlete were digitized and analyzed using a Peak Motus three‐dimensional motion analysis system. Thirty variables were examined for their effect on the distance of the throw. Correlation analysis indicated that measured distance was positively correlated with release speed (r = 0.97, p < 0.0003) and shoulder‐hip separation (r = 0.72, p < 0.06) and negatively correlated with release angle (r = ‐0.74, p < 0.056), rear knee angle at rear foot touchdown (r = ‐0.93, p < 0.003) and rear knee angle at release (r = ‐0.76, p < 0.047). Greater knee flexion angle at both rear foot touch down and release along with a neutral shoulder‐hip angle at release were identified as the most critical parameters for success among this sample of elite women shot putters. The unique observation about the knee positions at specific events should assist in new training and coaching developments.     

System approach to games and competitive playing: Reply to Lebed (2006)

Abstract

The maximal step length test has been proposed to evaluate the risk of falls among the elderly, although the test is confusing and prone to errors due to two types of test methods. The maximal double-step length test may be used to evaluate both leg function and the functional difference between the left and right legs, but its measurement and evaluation methods have not been studied extensively. The aims of the present study were to compare the maximal single- and double-step length tests, and to highlight differences between the sexes and between the dominant and non-dominant legs. Fifty healthy adults free from lower-limb disorders conducted the above step tests twice, once with the dominant and once with the non-dominant leg. The former test requires individuals to return the stepping leg to the original position or to draw the other leg to the step leg after stepping out maximally with either leg from a standing posture while maintaining body stability with the supporting leg. The latter test requires individuals to step forward with either leg maximally, after similarly stepping with the other leg and to draw the first stepping leg to the second stepping leg. The above tests are defined as the single- and double-step length test, respectively. Step lengths were measured in both tests, and these values were used for analysis. Correlations among step length tests conducted with the dominant and non-dominant legs were very high (r=0.82–0.97). Significant sex differences were found in all step length tests, and males were superior to females. No significant difference between legs was found in any test. In summary, the relationship between the maximal single- and double-step length tests was very high and step lengths showed a significant sex difference.     

Elicitation of Maximal Oxygen Uptake from Standing Bicycle Ergometry

Abstract

Twelve male university students were tested twice on each of three continuous max [Vdot]RO₂ protocols for treadmill running, pedaling on a bicycle ergometer while seated, and pedaling on a bicycle ergometer while standing. A comparison of the results failed to reveal any differences among protocols for pulmonary ventilation (max [Vdot]R_E). For max [Vdot]RO₂ (both liters [mdot] minute^-1 and ml [mdot] minute^-1. kg^-1) all differences were significant with the highest value associated with treadmill running, the intermediate with cycling in the standing position, and the lowest with cycling while seated. Max heart rate (HR) was significantly higher on the treadmill than on either bicycle protocol, and the respiratory exchange ratio (R) was higher on the sitting bicycle task than on the standing bicycle task. No other differences among protocols were significant. Although the reliability coefficients for all protocols (range was from r = .95 to r = .97) and the intercorrelation coefficients among protocols (range was r = .93 to r = .94) were quite high, the magnitude of the standard errors of estimate tended to limit the ability to predict a subject's max [Vdot]RO₂ on the treadmill based upon his measured max [Vdot]RO₂ employing either a sitting or standing bicycle protocol.     

Effects of precompetition state anxiety interventions on performance time and accuracy among amateur soccer players: Revisiting the matching hypothesis

Abstract

In this study, we tested the matching hypothesis, which contends that administration of a cognitive or somatic anxiety intervention should be matched to a participant's dominant anxiety response. Sixty-one male soccer players (mean age 31.6 years, s=6.3) were assigned to one of four groups based on their responses to the Competitive State Anxiety Inventory-2, which was modified to include a directional scale. Interventions were randomly administered in a counterbalanced order 10 min before each performance trial on a soccer skill test. The dominantly cognitive anxious group (n=17), the dominantly somatic anxious group (n=17), and the non-anxious control intervention group (n=14) completed a baseline performance trial. The second and third trials were completed with random administration of brief cognitive and somatic interventions. The non-anxious control group (n=13) completed three trials with no intervention. A mixed-model, Group×Treatment multivariate analysis of variance indicated significant (P<0.05) changes in cognitive anxiety intensity and somatic anxiety intensity, but not in state anxiety direction (P>0.05), or performance time or accuracy (P>0.05). The present findings do not provide support for the matching hypothesis for state anxiety intensity and direction, or for performance.     

Imposing a pause between the eccentric and concentric phases increases the reliability of isoinertial strength assessments

Abstract

This study analysed the effect of imposing a pause between the eccentric and concentric phases on the biological within-subject variation of velocity- and power–load isoinertial assessments. Seventeen resistance-trained athletes undertook a progressive loading test in the bench press (BP) and squat (SQ) exercises. Two trials at each load up to the one-repetition maximum (1RM) were performed using 2 techniques executed in random order: with (stop) and without (standard) a 2-s pause between the eccentric and concentric phases of each repetition. The stop technique resulted in a significantly lower coefficient of variation for the whole load–velocity relationship compared to the standard one, in both BP (2.9% vs. 4.1%; P = 0.02) and SQ (2.9% vs. 3.9%; P = 0.01). Test–retest intraclass correlation coefficients (ICCs) were r = 0.61–0.98 for the standard and r = 0.76–0.98 for the stop technique. Bland–Altman analysis showed that the error associated with the standard technique was 37.9% (BP) and 57.5% higher (SQ) than that associated with the stop technique. The biological within-subject variation is significantly reduced when a pause is imposed between the eccentric and concentric phases. Other relevant variables associated to the load–velocity and load–power relationships such as the contribution of the propulsive phase and the load that maximises power output remained basically unchanged.