The specific physical work in beach handball should be focused on improving the particular needs of the goalkeeper.
What specific needs do we have?
The movements we perform require greater flexibility. We must reserve part of the session for some kind of flexibility and joint mobility that will allow us to perform these movements. My suggestion is to do this work before starting the session with the rest of the team, as a warm-up.
Strength in the lower body is essential for two reasons. On the one hand, the movements we need must be very fast. For example, we must have time from the moment the thrower plants his feet to turn until he throws to go out and position ourselves in front of him, including the gesture we want to perform. On the other hand, the gestures in goal require us to work on jumps with one or two legs, lateral lifts, etc. (to raise the leg, spagat, etc.).
Lateral displacements are less important, given that the width of the field is smaller than on the court and the area is a rectangle (we don’t have to go all the way to the wings).
The strength of the upper body will allow us the speed of execution in the gestures with the arms. It is not necessary in the same way as on the court to prevent injuries, as the ball weighs less and is thrown with less force. One aspect that becomes more important in this sport is the long pass. While on the court it is important that the goalkeeper passes the ball well, on the beach it is vital that he does so. We must work on the strength aspects in the younger players to enable us to be dangerous offensively as soon as possible (for a direct goal or a long pass).
The goalkeeper’s endurance is key. We have to make very quick changes, both going out and coming in. We also need to get the ball back as quickly as possible, for the direct goal or the long pass. And all this on a soft surface like sand. It may not be necessary to work separately from the rest of the team, as they have very similar needs, but it is necessary to keep the goalkeeper in constant movement during the session. Changes every few shots, forcing them to start from the goal line after each shot, including work on ball recovery and long passes, tasks in which they have to get in and out of the field quickly, etc. Work as similar as possible to matches.
Working on stabilising the body is also a fundamental part of the goalkeeper’s physical work. Many gestures, especially when we move up a category, involve rectifying the initial gesture, which is very difficult to achieve without this stabilisation. It is interesting to work on proprioception, not so much to prevent injuries (which are less than on the court due to the type of surface) but to stabilise quickly. And, of course, work on the core.