would you explain what 'small-sided' soccer is?

Small-sided soccer games are tools used to develop, simultaneously, technical, tactical, physical and psychological characteristics of soccer players. They are often played in small pitch sizes (around 40x30m), with fewer number of players than the regular game (3x3, 4x4, for example) and different rules (offside, presence/absence of goals, touches allowed per possession, etc.). To see an example, I recomend the attached paper, recently published by my research group.

Best regards,

Gibson M. Praça.

Article Numerical superiority changes the physical demands of soccer...

Gibson, I did look @ some documents but none directly addressed the warm up. however these may help you

Castellano, J., Casamichana, D., & Dellal, A. (2013). Influence of game format and number of players on heart rate responses and physical demands in small-sided soccer games. The Journal of Strength & Conditioning Research, 27(5), 1295-1303.

Owen, A. L., Wong, D. P., Paul, D., & Dellal, A. (2012). Effects of a periodized small-sided game training intervention on physical performance in elite professional soccer. The Journal of Strength & Conditioning Research, 26(10), 2748-2754. 

Thanks a lot Ms. Abdi. I appreciate your ansewer. Wish you the best.

I understand that the warm up should reproduce, in a more gradual way, the specificity of the main session´s activities. The more specific the warm up, I assume we could expect more prophylaxis and performance effects. Find attached a few articles on the subject that could be of your interest. Regards.

 Dear Marcelo and Vincius, thanks for the answer and the papers.

Another question: have you found some evidence about the with or without ball warm-up protocols influence in subsequent game performance?

The warm-up is the first phase of work-ability or work-capacity -

http://www.strongfirst.com/what-is-work-capacity-part-ii/

In Russia and Eastern European countries this is in our textbooks. I teach it to our freshmen in sport university.

When we begin some work, we start gradually and after some time we reach the level of high stable work-ability (work-capacity). In sports this first phase is moved ahead of the activity and named "warm-up". The idea is that you begin the sport activity in  the phase of high stable work-ability - in order not to warm-up gradually during the practice or competition. Because if you do so, then you give a gift to your opponents- 15 to 20 minutes when they will be much better than you  in every aspect of the game.

Please pay attention that this is about physical work-ability, but also about mental work-ability. Many athletes warm-up while gossiping or thinking about other things. The result is that they enter the practice or competition in  the 2nd phase of work-ability physically but still in  the 1st phase psychologically. They will need more time in order to focus, turn on game-thinking, anticipation etc. So, again, they give to their opponents  the gift 15-20 min of ineffective game play. During these 15-29 minutes the game could be "resolved", the result could be defined.

So, you should warm-up both physically and psychologically, gradually involving the functions, processes, qualities that you will use during the game.

http://www.strongfirst.com/what-is-work-capacity-part-ii/

Besides the physiological and psychological aspects, I would also highlight the importance of the cognitive warm-up, from the tactical and strategical point of view, prior to competition, including in the warm-up sessions specific principles of the chosen system of play. Regarding the use of the ball, I also use the argument based on the specificity of the game, but I haven´t seen yet any scientific studies about the difference of warm-up sessions with or without the ball. It would be a very interesting study but how to evaluate the effects of both?

Small games very important and use it to warm up something clever coach of the availability of the fun factor and excitement and benefits technical skills

http://www.jsams.org/article/S1440-2440%2808%2900033-9/abstract

http://journals.lww.com/nsca-jscr/Abstract/2008/09000/Heart_Rate_Responses_During_Small_Sided_Games_and.10.aspx

http://link.springer.com/article/10.2165/11539740-000000000-00000#page-1

https://books.google.com.eg/books?hl=ar&lr=&id=nyFr-2uwPGoC&oi=fnd&pg=PA355&dq=small-sided+games&ots=DXp2SuAik2&sig=cGZwTcj6fJY4tGg2zbw2V3c5H8c&redir_esc=y#v=onepage&q=small-sided%20games&f=false

http://www.tandfonline.com/doi/abs/10.1080/02640410600811858#.Vd5aipcpDIU

http://www.sciencedirect.com/science/article/pii/S1440244007001508