PURPOSE: The aim of this study was to examine the reliability, validity and usefulness of the 30–15IFT in competitive female soccer players. METHODS: Seventeen elite female soccer players participated in the study. A within subject test-retest study design was utilized to assess the reliability of the 30–15 intermittent fitness test (IFT). Seven days prior to 30–15IFT, subjects performed a continuous aerobic running test (CT) under laboratory conditions to assess the criterion validity of the 30–15IFT. End running velocity (VCT and VIFT), peak heart rate (HRpeak) and maximal oxygen consumption (VO2max) were collected and/or estimated for both tests. RESULTS: VIFT (ICC = 0.91; CV = 1.8%), HRpeak (ICC = 0.94; CV = 1.2%), and VO2max (ICC = 0.94; CV = 1.6%) obtained from the 30–15IFT were all deemed highly reliable (p > 0.05). Pearson product moment correlations between the CT and 30–15IFT for VO2max, HRpeak and end running velocity were large (r = 0.67, p = 0.013), very large (r = 0.77, p = 0.02) and large (r = 0.57, p = 0.042), respectively. CONCLUSION: Current findings suggest that the 30–15IFT is a valid and reliable intermittent aerobic fitness test of elite female soccer players. The findings have also provided practitioners with evidence to support the accurate detection of meaningful individual changes in VIFT of 0.5 km/h (1 stage) and HRpeak of 2 bpm. This information may assist coaches in monitoring “real” aerobic fitness changes to better inform training of female intermittent team sport athletes. Lastly, coaches could use the 30–15IFT as a practical alternative to laboratory based assessments to assess and monitor intermittent aerobic fitness changes in their athletes.

Original scientific paper Purpose of the research was to compare the effects of dynamic and proprioceptive neuromuscular facilitation (PNF) stretching on knee isokinetic strength and power parameters. Sample size of 50 male athletes is represented as male athletes divided into sub-samples of 10 athletes at competitive level in karate (19 ± 2,4), taekwondo (20 ± 3,6), boxing (19,8 ± 4,3), football (15,1 ± 0,3) and track and field sprint (18,3 ± 2,6). Isokinetic parameters of the knee were measured using Biodex isokinetic system3, at two angular speeds 60 °/s and 180 °/s. Parameters were measured after dynamic stretching protocol and again 48 h later after PNF protocol. For karate and taekwondo fighters no statistically significant differences were found. For boxers, football players and sprinters the values of strength and power parameters were higher after dynamic warm-up protocol at a statistically significant level. Results of this study confirmed that dynamic stretching contributes to higher values of the strength and power of thigh muscles compared to proprioceptive neuromuscular facilitation.

AbstractBackgroundSoccer is the most popular sport worldwide, with a long history and currently more than 500 million active participants, of whom 300 million are registered football club members. On the basis of scientific findings showing positive fitness and health effects of recreational soccer, FIFA (Fédération Internationale de Football Association) introduced the slogan “Playing football for 45 min twice a week—best prevention of non-communicable diseases” in 2010.ObjectiveThe objective of this paper was to perform a systematic review and meta-analysis of the literature to determine the effects of recreational soccer on maximal oxygen uptake ($$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max).MethodsSix electronic databases (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) were searched for original research articles. A manual search was performed to cover the areas of recreational soccer, recreational physical activity, recreational small-sided games and $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max using the following key terms, either singly or in combination: recreational small-sided games, recreational football, recreational soccer, street football, street soccer, effect, maximal oxygen uptake, peak oxygen uptake, cardiorespiratory fitness, $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max. The inclusion criteria were divided into four sections: type of study, type of participants, type of interventions and type of outcome measures. Probabilistic magnitude-based inferences for meta-analysed effects were based on standardised thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations for baseline fitness.ResultsSeventeen studies met the inclusion criteria and were included in the systematic review and meta-analysis. Mean differences showed that $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max increased by 3.51 mL/kg/min (95 % CI 3.07–4.15) over a recreational soccer training programme in comparison with other training models. The meta-analysed effects of recreational soccer on $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max compared with the controls of no exercise, continuous running and strength training were most likely largely beneficial [effect size (ES) = 1.46; 95 % confidence interval (CI) 0.91, 2.01; I2 = 88.35 %], most likely moderately beneficial (ES = 0.68; 95 % CI 0.06, 1.29; I2 = 69.13 %) and most likely moderately beneficial (ES = 1.08; 95 % CI −0.25, 2.42; I2 = 71.06 %), respectively. In men and women, the meta-analysed effect was most likely largely beneficial for men (ES = 1.22) and most likely moderately beneficial for women (ES = 0.96) compared with the controls. After 12 weeks of recreational soccer with an intensity of 78–84 % maximal heart rate (HRmax), healthy untrained men improved their $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max by 8–13 %, while untrained elderly participants improved their $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max by 15–18 %. Soccer training for 12–70 weeks in healthy women resulted in an improvement in $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max of 5–16 %. Significant improvements in $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max have been observed in patients with diabetes mellitus, hypertension and prostate cancer.ConclusionRecreational soccer produces large improvements in $$ \dot{V}{\text{O}}_{2\;\hbox{max} } $$V˙O2max compared to strength training and no exercise, regardless of the age, sex and health status of the participants. Furthermore, recreational soccer is better than continuous endurance running, albeit the additional effect is moderate. This kind of physical activity has great potential for enhancing aerobic fitness, and for preventing and treating non-communicable diseases, and is ideal for addressing lack of motivation, a key component in physical (in)activity.