As a trainer, it's part of your role to get people in a receptive state for learning and to keep them engaged, interested and energised throughout the training.
There are lots of ways to do this, I won't go into all of them here. Let me just talk about energisers.
Energisers are activities which are meant to, well - energise people.
Many of the activities which are described as energisers have nothing to do with the training material. In fact, that's the point. One of the ways to energise people is to let them do something which has nothing to do with the course. It gives their minds a break.
Also, most energisers involve physical activity, getting people moving around.
This is important because sitting still for long periods leads to fatigue, simply because the blood isn't flowing and carrying oxygen round the body as well as it does when people are moving around.
So, these are two approaches to energisers - get away from the course material and get people moving.
You can use a number of activities - throwing a ball around, a treasure hunt around the room where people find hidden items, a game of charades, all kinds of team games which you can find in books or on the internet.
However, I think you need to take care with energisers.
If you're not careful, they can actually distract people and make it harder for you to get them focused back on the training. This can happen if they take too long or if they involve a lot of running about and people get "overexcited" as my Mother used to say. In other words, they get so involved in the energiser that they take a long time to settle again.
Also, it can be tempting to rely on energisers to make up for dull training materials or methods. Energisers should not be a substitute for making your training interactive and interesting.
You can, of course, use activities as part of the training itself - use games, quizzes, group work to get people moving around and inject some fun into the learning. Keep people energised throughout rather than leaving it for specific times, such as after lunch.
If you do get the sense at some point that energy is flagging, then change what you're doing. Use variety in your approach to keep people's interest and make sure everyone is involved in the learning, avoid too much presenting or lecturing which leads to people switching off.
I always remember a good example of an energiser going wrong from a course I ran several years ago. I asked one of the participants to come up with an energiser to use after lunch on the last day.
After everyone had finished eating, he asked them all to go outside to the car park. During lunch, he'd taken a screwdriver and removed the number plates from all the participants' cars. He'd hidden them in the grounds of the hotel.
People went mad. They couldn't believe he'd taken a screwdriver to their nice shiny cars and they weren't pleased about having to search the grounds for their number plates. The activity took ages, especially since he'd forgotten where he'd put most of them.
When they had finally found their plates, it took a long time to get them focused again, in fact we had to have a break to let them calm down.
I learned a few lessons from that, I must say.
So, yes - keep people energised and watch out for fatigue setting in, but do it mainly through your training methods and don't just rely on energisers to get you through the day.