A comparison of catch phase force-time characteristics during clean derivatives from the knee

The aim of this study was to compare load-absorption force-time characteristics of the clean from the knee (CK), power clean from the knee (PCK) and clean pull from the knee (CPK). Ten collegiate athletes (age 27.5 ± 4.2 years; height 180.4 ± 6.7 cm; mass 84.4 ± 7.8 kg), performed three repetitions each of the CK, PCK and CPK with 90% of their 1RM power clean on a force platform. The CK load-absorption duration (0.95 ± 0.35 s) was significantly longer compared to the CPK (0.44 ± 0.15 s; p 0.05, d = 1.08), with no differences between PCK and CPK (p > 0.05, d = 0.91). The CPK demonstrated the greatest mean force (2039 ± 394 N), which was significantly greater than the PCK (1771 ± 325 N; p = 0.012, d = 0.83), but not significantly different to the CK (1830 ± 331 N; p > 0.05, d = 0.60); CK and PCK were not different (p > 0.05, d = 0.18). Significantly more load-absorption work was performed during the CK (655 ± 276 J) compared to the PCK (288 ± 109 J; d = 1.75, p 0.05). Additionally, more load-absorption work was performed during the CPK compared to the PCK (d = 1.90, p = 0.032). Inclusion of the catch phase during the CK does not provide any additional stimulus in terms of mean force or work during the load-absorption phase compared to the CPK, while the CPK may be beneficial in training rapid force absorption due to high force and a short duration

Load absorption force-time characteristics following the second pull of weightlifting derivatives

The purpose of this study was to compare the load absorption force-time characteristics of weightlifting catching and pulling derivatives. Twelve resistance-trained men performed repetitions of the hang power clean (HPC), jump shrug (JS), and hang high pull (HHP) on a force platform with 30, 45, 65, and 80% of their one repetition maximum (1RM) HPC. Load absorption phase duration, mean force, and work were calculated from the force-time data. The HHP produced a significantly longer load absorption phase duration compared to the HPC (p < 0.001, d = 3.77) and JS (p < 0.001, d = 5.48), while no difference existed between the HPC and JS (p = 0.573, d = 0.51). The JS produced significantly greater load absorption mean forces compared to the HPC (p < 0.001, d = 2.85) and HHP (p < 0.001, d = 3.75), while no difference existed between the HPC and HHP (p = 0.253, d = 0.37). Significantly more load absorption work was performed during the JS compared to the HPC (p < 0.001, d = 5.03) and HHP (p < 0.001, d = 1.69), while HHP load absorption work was also significantly greater compared to the HPC (p < 0.001, d = 4.81). The weightlifting pulling derivatives examined in the current study (JS and HHP) produced greater load absorption demands following the second pull compared to the weightlifting catching derivative (HPC). The JS and HHP may be used as effective training stimuli for load absorption during impact tasks such as jumping

Comparing the effectiveness of a short-term vertical jump vs. weightlifting program on athletic power development

Efficient training of neuromuscular power and the translation of this power to sport-specific tasks is a key objective in the preparation of athletes involved in team-based sports. The purpose of the current study was to compare changes in center of mass (COM) neuromuscular power and performance of sport-specific tasks following short-term (6-week) training adopting either Olympic Style Weightlifting (WL) exercises or vertical jump (VJ) exercises. Twenty six recreationally active males (18-30 years; height: 178.7±8.3 cm; mass: 78.6±12.2 kg) were randomly allocated to either a WL or VJ training group and performance during the countermovement jump (CMJ), squat jump (SJ), depth jump (DJ), 20m sprint and the 5-0-5 agility test assessed pre- and post-training. Despite the WL group demonstrating larger increases in peak power output during the CMJ (WL group: 10% increase, d=0.701; VJ group: 5.78% increase, d=0.328) and SJ (WL group: 12.73% increase, d=0.854; VJ group: 7.27% increase, d=0.382), no significant between-group differences were observed in any outcome measure studied. There was a significant main effect of time observed for the three vertical jumps (CMJ, SJ, DJ), 0-5m and 0-20m sprint times, and the 5-0-5 agility test time, which were all shown to improve following the training (all main effects of time p<0.01). Irrespective of the training approach adopted by coaches or athletes, addition of either WL or VJ training for development of power can improve performance in tasks associated with team-based sports, even in athletes with limited pre-season training periods

Is there a relationship between the overhead press and split jerk maximum performance? Influence of sex

The aims of this study were to (I) determine the differences and relationship between the overhead press and split jerk performance in athletes involved in weightlifting training, and (II) explore the magnitude of these differences in one-repetition maximum (1RM) performances between sexes. Sixty-one men (age: 30.4 ± 6.7 years; height: 1.8 ± 0.5 m; body mass 82.5 ± 8.5 kg; weightlifting training experience: 3.7 ± 3.5 yrs) and 21 women (age: 29.5 ± 5.2 yrs; height: 1.7 ± 0.5 m; body mass: 62.6 ± 5.7 kg; weightlifting training experience: 3.0 ± 1.5 yrs) participated. The 1RM performance of the overhead press and split jerk were assessed for all participants, with the overhead press assessed on two occasions to determine between-session reliability. The intraclass correlation coefficients (ICC) and 95% confidence intervals showed a high reliability for the overhead press ICC = 0.98 (0.97 – 0.99). A very strong correlation and significant differences were found between the overhead press and split jerk 1RM performances for all participants (r = 0.90 [0.93 – 0.85], 60.2 ± 18.3 kg, 95.7 ± 29.3 kg, p ≤ 0.001). Men demonstrated stronger correlations between the overhead press and split jerk 1RM performances (r = 0.83 [0.73-0.90], p ≤ 0.001) compared with women (r = 0.56 [0.17-0.80], p = 0.008). These results provide evidence that 1RM performance of the overhead press and split jerk performance are highly related, highlighting the importance of upper-limb strength in the split jerk maximum performance

Women's job quality across family life stages: An analysis of female employees across 27 European countries

There is little empirical evidence on how working conditions affect women’s employment and fertility choices, despite a number of studies on the impact of individual-level and institutional factors. The article addresses this gap by examining how family life stages are related to particular aspects of job quality among employed women in 27 European countries. The central argument of the analysis is that high-quality jobs are conducive to both transitions to motherhood and employment after childbirth as women select into these roles. Accordingly, mothers of young children, if employed, are expected to have relatively better quality jobs. Four dimensions of job quality are considered: job security, career progression, working time and intrinsic job quality. The results indicate that mothers with young children are more likely to hold high-quality jobs than women at other life stages with respect to working time quality and job security, but with some variation across countries for job security. The findings highlight the importance of high-quality jobs for women’s fertility decisions and labour market attachment after childbirth, with implications for European employment policy

Relationships between Challenge Tour golfers’ clubhead velocity and force producing capabilities during a countermovement jump and isometric mid-thigh pull

A number of field-based investigations have evidenced practically significant relationships between clubhead velocity (CHV), vertical jump performance and maximum strength. Unfortunately, whilst these investigations provide a great deal of external validity, they are unable to ascertain vertical ground reaction force (vGRF) variables that may relate to golfers’ CHVs. This investigation aimed to assess if the variance in European Challenge Tour golfers’ CHVs could be predicted by countermovement jump (CMJ) positive impulse (PI), isometric mid-thigh pull (IMTP) peak force (PF) and rate of force development (RFD) from 0–50 ms, 0–100 ms, 0–150 ms and 0–200 ms. Thirty-one elite level European Challenge Tour golfers performed a CMJ and IMTP on dual force plates at a tournament venue, with CHV measured on a driving range. Hierarchical multiple regression results indicated that the variance in CHV was significantly predicted by all four models (model one R2 = 0.379; model two R2 = 0.392, model three R2 = 0.422, model four R2 = 0.480), with Akaike’s information criterion indicating that model one was the best fit. Individual standardised beta coefficients revealed that CMJ PI was the only significant variable, accounting for 37.9% of the variance in European Challenge Tour Golfers’ CHVs

Working conditions and Work-Family Conflict in German hospital physicians: psychosocial and organisational predictors and consequences

<p>Abstract</p> <p>Background</p> <p>Germany currently experiences a situation of major physician attrition. The incompatibility between work and family has been discussed as one of the major reasons for the increasing departure of German physicians for non-clinical occupations or abroad. This study investigates predictors for one particular direction of Work-Family Conflict – namely work interfering with family conflict (WIF) – which are located within the psychosocial work environment or work organisation of hospital physicians. Furthermore, effects of WIF on the individual physicians' physical and mental health were examined. Analyses were performed with an emphasis on gender differences. Comparisons with the general German population were made.</p> <p>Methods</p> <p>Data were collected by questionnaires as part of a study on <it>Psychosocial work hazards and strains of German hospital physicians </it>during April–July 2005. Two hundred and ninety-six hospital physicians (response rate 38.9%) participated in the survey. The Copenhagen Psychosocial Questionnaire (COPSOQ), work interfering with family conflict scale (WIF), and hospital-specific single items on work organisation were used to assess WIF, its predictors, and consequences.</p> <p>Results</p> <p>German hospital physicians reported elevated levels of WIF (mean = 74) compared to the general German population (mean = 45, <it>p </it>< .01). No significant gender difference was found. Predictors for the WIF were lower age, high quantitative demands at work, elevated number of days at work despite own illness, and consequences of short-notice changes in the duty roster. Good sense of community at work was a protective factor. Compared to the general German population, we observed a significant higher level of quantitative work demands among hospital physicians (mean = 73 vs. mean = 57, <it>p </it>< .01). High values of WIF were significantly correlated to higher rates of personal burnout, behavioural and cognitive stress symptoms, and the intention to leave the job. In contrast, low levels of WIF predicted higher job satisfaction, better self-judged general health status, better work ability, and higher satisfaction with life in general. Compared to the German general population, physicians showed significantly higher levels of individual stress and quality of life as well as lower levels for well-being. This has to be judged as an alerting finding regarding the state of physicians' health.</p> <p>Conclusion</p> <p>In our study, work interfering with family conflict (WIF) as part of Work-Family Conflict (WFC) was highly prevalent among German hospital physicians. Factors of work organisation as well as factors of interpersonal relations at work were identified as significant predictors for WIF. Some of these predictors are accessible to alteration by improving work organisation in hospitals.</p