The novel coronavirus disease 2019 (COVID-19) seems to be having a major impact on physical activity behaviours globally. The pandemic has forced many people around the world to stay at home and self-isolate for a period of time. WHO recommends 60 min/day of moderate-to-vigorous physical activity for 6-17-yr-olds, and 75 min/wk of vigorous or 150 min/wk of moderate physical activity for adults and elderly, including 3 and 2 days/wk, respectively, with muscle and bone strengthening. Practical recommendations for staying active at home, with aerobic exercise training on a bike or rowing ergometer, bodyweight training, dance and active video gaming, can aid to counteract the detrimental physical and mental sideeffects of the COVID-19 protective lifestyle regulations. This commentary provides useful information on home-based physical activity for sedentary people across the lifespan, including children and adolescence, that can be undertaken during the present pandemic or other outbreaks of infectious disease.

INTRODUCTION: This paper aimed to systematically review and meta-analyze the training effects of small-sided games (SSG) on physical fitness and specific skills related to team sport according to the level of play and the period of the season. EVIDENCE ACQUISITION: The search covered the following electronic databases (PubMed, Google Scholar, and ScienceDirect). The publications' search period ranged from 2000 to 2016. The terms (smallsided game, training, skill-based game, aerobic fitness, sprint, agility, jump and team sports) were used either singularly or combined in a systematic sequence. Appraisal of 16 articles (15 were meta-analysed) was performed after the application of exclusion criteria and quality assurance processes and the standardized mean effects were measured using random effects. EVIDENCE SYNTHESIS: The results revealed that SSG training had a large beneficial effect on maximal oxygen uptake [ O2max] (effect size (ES) = 1.94; 95 % CI 0.15, 3.74; I 2 = 94 %), agility (ES = -1.49; 95% CI -2.27, -0.71; I 2 = 80%), and repeated sprint ability (ES = -1.19; 95% CI -2.17, -0.21; I 2 = 53%). There was a moderate beneficial effect on 10-and 20-m

Recreational soccer (RS) is becoming a popular alternative to the classical continuous exercise mode used for the improvement of cardiovascular and metabolic fitness in untrained people. The objective of this paper was to conduct a detailed systematic review of the literature, identifying the physiological responses to RS and the training effects of RS on aerobic fitness and health in untrained healthy individuals and clinical patients. PubMed, Google Scholar and ScienceDirect databases were searched using terms related to recreational soccer. Inclusion criteria were randomized controlled trials (RCT) that assessed acute physiological responses to RS or the training effects of RS on physical fitness and health in sedentary, untrained subjects of any age or health status. All studies were assessed for methodological quality using the PEDro scale. Thirty-five articles met the inclusion criteria; seven examined the acute response to RS, and 28 assessed training effects. Clear evidence was found that RS had positive effects on many health-related indices and variables, including VO2max (gains of 7-16%), blood pressure (reductions of 6-13 mmHg), body composition (decreased fat mass and improved indices of bone health), and metabolic and cardiac function. These positive effects were observed in both healthy individuals and clinical patients, irrespective of age or sex. Although this review provides clear evidence of the positive effects of RS on health, most studies had limitations of methodology (an average PEDro score < 6). Furthermore, many of the training studies were from a small number of research groups. Future studies should be extended to other countries and institutions to ensure generality of the results. Regular RS training leads to significant cardiovascular and muscular adaptations and gains of health both in sedentary individuals and clinical patients at all ages, suggesting that RS is a potentially highly motivational method to enhance population health.

A. Seabra http://orcid.org/0000-0002-6788-4555 A. N. Rebelo http://orcid.org/0000-0001-9105-7421 S. Póvoas http://orcid.org/0000-0002-6661-3673 C. Castagna http://orcid.org/0000-0002-8320-6404 Z. Milanovic http://orcid.org/0000-0002-3224-0506 M. B. Randers

Background: Small-sided soccer games (SSSG) are a specific exercise regime with two small teams playing against each other on a relatively small pitch. There is evidence from original research that SSSG exposure provides performance and health benefits for untrained adults. Objectives: The aim of this systematic review was to summarize recent evidence on the acute and long-term effects of SSSG on physical fitness, physiological responses, and health indices in healthy untrained individuals and clinical populations. Materials and Methods: This systematic literature search was conducted in four electronic databases (PubMed, Web of Science, SPORTDiscus) from inception until June 2019. The following key terms (and synonyms searched for by the MeSH database) were included and combined using the operators "AND", "OR", "NOT": ((soccer OR football) AND ("soccer training" OR "football training" OR "soccer game*" OR "small-sided soccer game*") AND ("physical fitness" OR "physiological adaptation*" OR "physiological response*" OR health OR "body weight" OR "body mass" OR "body fat" OR "bone composition" OR "blood pressure")). The search syntax initially identified 1,145 records. After screening for titles, abstracts, and full-texts, 41 studies remained that examined the acute (7 studies) and long-term effects (34 studies) of SSSG-based training on physical fitness, physiological responses, and selected health indices in healthy untrained individuals and clinical populations. Results: No training-related injuries were reported in the 41 acute and long-term SSSG studies. Typically, a single session of SSSG lasted 12 to 20 minutes (e.g. 3x4 min with 3 min rest or 5x4 min with 4 min rest) involving 4 to 12 players (2 vs. 2 to 6 vs. 6) at an intensity ≥80% of HR max. Following single SSSG sessions, high cardiovascular and metabolic demands were observed. Specifically, based on the outcomes, the 7 acute studies reported average heart rates (HR) ≥80% of HR max (165-175 bpm) and mean blood lactate concentrations exceeding 5 mmol/l (4.5-5.9 mmol/l) after single SSSG sessions.