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  • Author: Aleksandra Mostowik x
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A systematic review of the main factors that determine agility in sport using structural equation modeling

Abstract

While tests of basic motor abilities such as speed, maximum strength or endurance are well recognized, testing of complex motor functions such as agility remains unresolved in current literature. Therefore, the aim of this review was to evaluate which main factor or factor structures quantitatively determine agility. In methodological detail, this review focused on research that explained or described the relationships between latent variables in a factorial model of agility using approaches such as principal component analysis, factor analysis and structural equation modeling. Four research studies met the defined inclusion criteria. No quantitative empirical research was found that tried to verify the quality of the whole suggested model of the main factors determining agility through the use of a structural equation modeling (SEM) approach or a confirmatory factor analysis. From the whole structure of agility, only change of direction speed (CODS) and some of its subtests were appropriately analyzed. The combination of common CODS tests is reliable and useful to estimate performance in sub-elite athletes; however, for elite athletes, CODS tests must be specific to the needs of a particular sport discipline. Sprinting and jumping tests are stronger factors for CODS than explosive strength and maximum strength tests. The authors suggest the need to verify the agility factorial model by a second generation data analysis technique such as SEM.

Open access
The Effect of Physical And Mental Stress on the Heart Rate, Cortisol and Lactate Concentrations in Rock Climbers

Abstract

Rock climbing is a physical activity that not only causes an increase in muscle tension, heart rate and blood pressure, but also results in the elevation of stress hormones including cortisol. It has not been established which of the above mentioned variables serve as the most accurate indicator of rock climbing-induced physical and mental stress. The aim of this study was to evaluate the effect of physical activity, short-term fatigue and mental demand on heart rate (HR), salivary cortisol (C) and blood plasma lactate (LA) concentrations in rock climbers under laboratory conditions. Twelve male and female rock climbers of comparable climbing performance (5a – 6b OS) were recruited. The participants completed two routes of different climbing difficulty (effect of physical demand), repeated a difficult route with a short 5-min recovery period three times (effect of fatigue), and repeated a difficult lead climb (effect of mental demand). Heart rate as well as C and LA concentrations were determined. The results indicated that more difficult climbing routes elicited increases in HR (especially relative values) and LA concentrations, whereas fatigue accumulation had an effect on climbing HR and relative C concentration values. Lead climbing only caused an increase in climbing HR. Based on the results it was concluded that HR was a good indicator of physical and mental stress intensity. Performing the same difficult route three times with a short recovery period in-between turned out to be the most demanding task and resulted in the highest increase of the cortisol concentration. Dynamics of changes in lactate concentrations depend on muscle loading (local muscular effort), lactate clearance and technical/tactical skills of the climber.

Open access
The Influence of Grip Width on Training Volume During the Bench Press with Different Movement Tempos

Abstract

The aim of the study was to determine the effect of the wide-grip bench press (WGBP) and the close-grip bench press (CGBP) on the number of performed repetitions (REPs) and time under tension (TUT) using a variable tempo of movement. Twenty (20) women experienced in resistance training were enrolled in the study (1RM-CGBP = 55.2 ± 9.5 kg; 1RM-WGBP = 52.7 ± 8.5 kg). Participants performed 5 sets of the BP with a maximal number of REPs at 70%1RM. Different tempos of movement, i.e., slow (6/0/X/0) and fast (2/0/X/0), and grip widths, i.e., the CGBP and the WGBP, were employed. The following variables were registered: maximal number of repetitions in every set (REPSet1-5), total number of repetitions performed in 5 sets (TREP), maximal time under tension in every set (TUTSet1-5) and total time under tension in 5 sets (TTUT). The two-way ANOVA revealed statistically significant differences between the WGBPFAST and the WGBPSLOW in TUTSet1-5 (p < 0.05) and TTUT (p < 0.01), as well as between the CGBPFAST and the CGBPSLOW in TUTSet1-5 (p < 0.01) and TTUT (p < 0.01). Significant differences between the WGBPFAST and the WGBPSLOW were also observed in REPSet1-5 (p < 0.01) and TREP (p < 0.01) as well as between the CGBPFAST and the CGBPSLOW in REPSet1-5 (p < 0.01) and TREP (p < 0.01). No significant differences between the WGBPSLOW and the CGBPSLOW nor the WGBPFAST and the CGBPFAST were found. The study demonstrates that the tempo of movement, regardless of the width grip, has a significant effect on the volume of effort in resistance training.

Open access
Effects of Krankcycle Training on Performance and Body Composition in Wheelchair Users

Abstract

Innovation in training equipment is important for increasing training effectiveness, performance and changes in body composition, especially in wheelchair users with paraplegia. The main objective of a workout session is to induce an adaptation stimulus, which requires overload of involved muscles by voluntary effort, yet this overload may be highly influenced by the size of the spinal cord lesion. Krancykl construction is designed to allow exercise on any wheelchair and with adjustable height or width of crank handles, where even the grip handle may be altered. The aim of this study was to determine the differences in body composition, performance and the rate of perceived exertion (RPE) in paraplegics with a different level of paralyses after a 12 week training programme of a unilateral regime on Krankcycle equipment (a crank machine). The study sample included four men and one women at a different spine lesion level. The 12 weeks programme was successfully completed by four participants, while one subject got injured during the intervention process. Three participants were paraplegics and one was quadriplegic with innervation of the biceps humeri, triceps humeri and deltoideus. The Krankcycle 30 min programme was followed by four other exercises, which were performed after themselves rather than in a circuit training manner as the latter would result in much longer rest periods between exercises, because paraplegics have to be fixed by straps during exercise on hydraulic machines. The RPE after the workout decreased following the twelve week adaptation period.

Open access
The Body Mass Index and Waist Circumference as Predictors of Body Composition in Post CSCI Wheelchair Rugby Players (Preliminary Investigations)

Abstract

The enforced sedentary lifestyle and muscle paresis below the level of injury are associated with adipose tissue accumulation in the trunk. The value of anthropometric indicators of obesity in patients with spinal cord injuries has also been called into question. We hypothesized that the Body Mass Index recommended by the WHO to diagnose obesity in general population has too low sensitivity in case of wheelchair rugby players.

The study group comprised 14 wheelchair rugby players, aged 32.6 ± 5.1 years, who had sustained CSCI (paralysis of lower limbs and upper extremities). The research tool was the Tanita Viscan visceral and trunk fat analyzer AB140 using the abdominal bioelectrical impedance analysis (BIA) to estimate the visceral fat level (Vfat) and trunk fat percentage (Tfat). The AB140 analyzer also allowed the measurement of body composition of those individuals who could not assume an upright position. Our analyses revealed high and very high correlation coefficients between Vfat and WC (r=0.9), WHtR (r=0.7) and Tfat (r=0.9) whereas the correlation between Vfat and the BMI was weak, especially in the subgroup with Vfat < 13.5% ( r=0.2). The subgroup with Vfat>13.5 exhibited a moderate-level relationship between the BMI and visceral fat increase. It was concluded that the BMI had a low sensitivity for predicting obesity risk in wheelchair rugby players after CSCI. The sensitivity of WC measurement was higher and thus, it may be stated that it constitutes an objective tool for predicting obesity risk in post-CSCI wheelchair rugby players.

Open access
Kinetic and Kinematic Differences in a Golf Swing in One and Both Lower Limb Amputees

Abstract

Amputee golfers need to cope with the absence of sole proprioception, a decreased range of swing motion and other factors which should be recognized for training purposes. The aim of this study was to determine the kinetic and kinematic differences in the golf swing in one leg and two legs amputees. The participants consisted of two males and one female at a professional or amateur level with a different degree of disability. Each participant was taped by 3D markers and performed five golf swings with the iron 6. The intraclass correlation coefficient (ICC) did not vary between individuals in kinematics, however, it was low in kinetic variables of two leg amputees. The Kendal rank correlation showed a significant relationship between the level of amputation and a large number of kinetic and kinematic variables such as X factor, O factor, S factor and individual body angles. The fluency and similarity of the golf swing did not depend on the level of amputation. One lower limb amputation did not seem to increase movement variability contrary to two lower limb amputation. The most variable parameter was a weight-shift in all golfers. The takeaway and horizontal force angle depended on the level of amputation rather than individual technique, thus, their modification by training may be difficult. Estimation of golf swing „mistakes“ in amputees in respect to the leading arm in an early follow or late follow position appeared to be useless.

Open access