1.1 The loss of earning capacity in this case constitutes both a present and prospective loss. A present loss refers to the loss of income or earning capacity that has already occurred as a result of the injury, such as the fact that Mrs Vusani will no longer be able to work as a physiotherapist. On the other hand, a prospective loss refers to the potential future loss of income or earning capacity that Mrs Vusani may suffer as a result of her inability to work in the future.
In the case of Grobler v Naspers Bpk 2004 (6) SA 295 (SCA), the South African Supreme Court of Appeal held that prospective damages for loss of earning capacity consist of two legs - present loss (past financial disadvantage) and future loss (future financial disadvantage). Mrs Vusani would be entitled to claim for both present and prospective loss of earning capacity as part of her damages due to the injuries sustained at the water park.
1.2 In relation to the application of the 'once and for all' rule in this case, the rule states that a plaintiff can only claim once for all the damages they have or will suffer as a result of the defendant's negligence. In this case, Mrs Vusani's prospective loss of earning capacity would fall under the future loss leg of the prospective damages.
Visser & Potgieter (The Law of Damages 4th ed) explain that the 'once and for all' rule does not prevent a plaintiff from claiming for prospective loss of earning capacity separately from present loss. Therefore, Mrs Vusani would be able to claim for both her present loss of earning capacity (the fact that she can no longer work as a physiotherapist) and her prospective loss of earning capacity (the potential future loss of income) as separate components of her damages.