Reliability and validity of field-based fitness tests in youth soccer players

This study aimed to establish between-day reliability and validity of commonly used field-based fitness tests in youth soccer players of varied age and playing standards, and to discriminate between players without (“unidentified”) or with (“identified”) a direct route to professional football through their existing club pathway. Three-hundred-and-seventy-three Scottish youth soccer players (U11–U17) from three different playing standards (amateur, development, performance) completed a battery of commonly used generic field-based fitness tests (grip dynamometry, standing broad jump, countermovement vertical jump, 505 (505COD) and T-Drill (T-Test) change of direction and 10/20 m sprint tests) on two separate occasions within 7–14?days. The majority of field-based fitness tests selected within this study proved to be reliable measures of physical performance (ICC?=?0.83–0.97; p?p?2 (7)?=?101.646, p?相似文献   

The role of athlete narcissism in moderating the relationship between coaches' transformational leader behaviors and athlete motivation

Leadership research that examines follower characteristics as a potential moderator of leadership effectiveness is lacking. Within Bass's (1985) transformational leadership framework, we examined follower narcissism as a moderator of the coach behavior-coach effectiveness relationship. Youth athletes (male = 103, female = 106) from the Singapore Sports Academy (mean age = 14.28, SD = 1.40 years) completed the Differentiated Transformational Leadership Inventory (Callow, Smith, Hardy, Arthur, & Hardy, 2009), the Narcissistic Personality Inventory (Raskin & Terry, 1988), and indices of follower effort. Multilevel analyses revealed that athlete narcissism moderated the relationship between fostering acceptance of group goals and athlete effort and between high performance expectations and athlete effort. All the other transformational leader behaviors demonstrated main effects on follower effort, except for inspirational motivation.     

Children's Relationships with Peers: Differential Associations with Aspects of the Teacher-Child Relationship

Associations between children's social competence with peers and differential aspects of their teacher-child relationships were examined in a longitudinal sample of 48 4-year-old children enrolled in child care as infants. Toddler security with teacher was negatively associated with hostile aggression and positively with complex peer play and gregarious behaviors. Prosocial behaviors and withdrawing behaviors were associated with preschool security with teacher. Dependence on teachers as a preschooler was associated with social withdrawal and hostile aggression. Positive toddler teacher socialization was associated with higher perceived peer acceptance. Preschool teacher negative socialization was negatively associated with complex peer play, teacher ratings of hesitancy, friendly enactment, and accidental attribution and positively related to teacher ratings of difficulty.     

Iron status in Winter Olympic sports

Iron status was surveyed amongst 92 Winter Olympic sport athletes from Nordic and Alpine skiing, figure and speed skating and ice hockey. Haemoglobin and serum ferritin values were obtained by physicians as part of a monitoring programme, since iron deficiency would have an adverse effect on maximal performance. Four (7%) of 56 men were anaemic (Hb < 14.0 gdl^‐1) and three (8%) of 36 women had haemoglobin values less than 12.0 gdl^‐1. Nine men (16%) and 14 women (39%) had prelatent iron deficiency (serum ferritin < 30 ng ml^‐1). Ice hockey had the lowest while Nordic skiing had the highest incidence of sub‐optimal iron status. A total of 50% of Nordic women skiers had prelatent iron deficiency and 7% were anaemic. An equal percentage of women speed skaters were low in serum ferritin as well. Only one of 20 male ice hockey players was low in serum ferritin. These results suggest there would be value in instituting screening procedures for iron status in Winter Olympic Sports.