## 1 Introduction  
Olymp weightlifting and track and field throwing events are two of the most power-demanding athletic activities [1]. Power athletes, such as weightlifters and track and field throwers, dedicate a large part of their preparation to resistance training programs to enhance competitive lifting and throwing performance, respectively [2; 3; 4]. Weightlifting includes the snatch and the clean and jerk, two multijoint movements that require high-power production and the ability of the athletes to produce a large amount of force rapidly [5]. Track and field throwing events include the shot put, the javelin, the hammer and the discus throw. Performance in these events depends, to a considerable extend, on fast force application on the throwing implement [6; 7]. For these reasons, weightlifters and throwers share several similarities in their training programs. Both groups of athletes mainly use resistance exercises, such as the snatch, the back squat and the clean and jerk, performed explosively, as well as sprints and glyometric exercises, and they frequently evaluate their maximum strength (1-RM) [2; 3]. However, weightlifters use higher resistance loads during their year-round training (>85% of 1-RM) compared to throwers, who use both light (\(\leq\)30% of 1-RM) and heavy resistance loads (\(\geq\)80% of 1-RM) [8]. Moreover, throwers aim to overcome a constant external load (the implement's mass) with maximum velocity compared to weightlifters, who aim to lift the heaviest possible load during snatch and clean and jerk. These similarities and differences between weightlifting and track and field throwing events may dictate different training-induced adaptations with respect to factors such as the rate of force development (RFD), the amount of lean mass and muscle architecture characteristics. Regarding RFD, it is thought to be a key factor influencing successful performance in power sports [6; 9]. RFD can be assessed by the force-time curve during both dynamic and isometric muscle actions and evaluates the force that can be applied in short time periods ranging from 0 to 250 ms [9; 10; 11; 12]. It has been proposed that RFD is subject to numerous biological and non-biological factors that are dependent on time, training type and training background [9; 12]. For example, early RFD (\(<\)100 ms from the onset of muscle contraction) seems to be primarily determined by neural activation [9] and, at least in well-trained power athletes, by the percentage area of muscle occupied (\(\%\)CSA) of type IIx muscle fibres [12]. In contrast, lean mass, fibre-type composition, muscle architecture and maximum strength seem to be associated with late RFD (\(>\)100 ms from the onset of muscle contraction) [6; 9; 12]. Power athletes have higher RFDs compared to strength-trained, endurance-trained or sedentary participants, mostly due to longitudinal power training, resulting in type IIx maintenance, lean mass and strength increase [12; 13; 14]. Track and field throwers have a high percentage of type II muscle fibres [15], and they maintain a high percentage of type IIx muscle fibres, even after the heavy winter preparation phase [14]. On the contrary, weightlifters have a high percentage of type IIa muscle fibres and fibre area [16; 17]. Nevertheless, weightlifters and throwers have similar RFD acceleration times during the second pull of the barbell (150-200 ms) [18; 19] and the final thrust of the throwing implement (150-240 ms) [20; 21], respectively. However a comparison of RFDs is lacking between these groups of highly trained power athletes. Lean body mass is also a positive contributing factor in strength power sports. Training-induced increases in lean mass are significantly correlated with increases in RFD in track and field throwers [6]. Moreover, lean mass is closely correlated with throwing performance, 1-RM strength and power in throwers [2; 7; 22]. Lean mass is significantly correlated with weightlifting performance in young [23], elite male [24] and well-trained female weightlifters [25].