The races are run in divisions, each containing 17 crews. The number of crews in each bottom division varies yearly depending on new entrants. Each crew consists of eight rowers and one coxswain. Unlike the May Bumps, rowers trialling for places in university crews are not allowed to take part in the Lents. A total of 120 crews took part in 2020, totalling around 1080 participants. There are currently four divisions for men's crews (referred to as M1, M2 ... M4) and four divisions for women's crews (similarly W1 to W4). Both M4 and W4 are "short" divisions which marshall together; W4 goes off 5 minutes separated from M4 whereas other divisions are separated by 40 minutes. The divisions represent an overall race order, with Division 1 at the top. The ultimate aim is to try to finish "Head of the River" (also said as gaining the 'Headship'), i.e. first position in Division 1.