## 4 Discussion  
Findings revealed significant improvements in abdominal strength, endurance, and flexibility in school-aged athletes following a 12-week core strengthening training as well as weight training. However, abdominal strength and endurance improved slightly more in the weight training group than in the core strength training group, whilst flexibility \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Test** & **Pre-Post** & **Group** & **Mean \(\pm\) SD** & \(p\) **Values** \\ \hline Number of sit-ups (\#) & Pre & G1 & 18.70 \(\pm\) 3.20 & 0.13 \\  & & G2 & 17.60 \(\pm\) 3.29 & \\  & & G3 & 17.20 \(\pm\) 3.20 & \\ \hline Number of sit-ups (\#) & Post & G1 & 22.21 \(\pm\) 3.50 & 0.00 \\  & & G2 & 21.60 \(\pm\) 3.63 & \\  & & G3 & 16.39 \(\pm\) 2.69 & \\ \hline Distance covered in 12 min run test (m) & Pre & G1 & 1817 \(\pm\) 185.78 & 0.97 \\  & & G2 & 1806 \(\pm\) 237.25 & \\  & & G3 & 1813 \(\pm\) 224.69 & \\ \hline Distance covered in 12 min run test (m) & Post & G1 & 2008.97 \(\pm\) 214.79 & 0.00 \\  & & G2 & 2002.59 \(\pm\) 283.32 & \\  & & G3 & 1778.15 \(\pm\) 205.28 & \\ \hline Sit and reach distance (cm) & Pre & G1 & 23.48 \(\pm\) 2.75 & 0.96 \\  & & G2 & 23.66 \(\pm\) 2.92 & \\  & & G3 & 23.46 \(\pm\) 3.06 & \\ \hline Sit and reach distance (cm) & Post & G1 & 25.96 \(\pm\) 2.38 & 0.00 \\  & & G2 & 25.86 \(\pm\) 2.55 & \\  & & G3 & 21.76 \(\pm\) 2.56 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Pre- and post-12-week changes in physical fitness variables among school-aged athletes. increased slightly more in the core strength training group than in the weight training group. This may be ascribed to adaptations to exercises used. While the core strengthening training included exercises such as side planks, bridges, leg-raises, flutter kicks, butterfly sit-ups, dead bugs, and rolling like a ball, the weight training included exercises such as military presses, back presses, biceps curls, bench presses, heel raises, half squats, and lunges. These findings are in line with those of previous studies, which demonstrated a significant increase in muscle power and strength following weight training. For instance, maximal lifting power and isometric hip and trunk extension strength increased after an 8-week training, including maximal voluntary co-contraction of abdominal muscles, in young adult men [31]. Core/torso stiffness improved more after a 6-week isometric compared to a dynamic core training [32]. However, core strength training can also be effective in improving various physical fitness variables. Similar to our study, the endurance and strength of the core muscles improved after a 10-week Quad-Core training in school football players [20]. Regarding the flexibility, spine range of motion, lateral flexibility, dynamic balance, and endurance and/or strength of the back, abdominal and leg muscles improved after an 8-week core muscle training program using BOSU and a Swiss ball in male university students [33]. The range of motion in the stand and reach test also improved after an 8-week training program using a foam roll, without a decrease in muscle performance, strength endurance of the core muscles, or balance [34]. Strength of the core muscles increased following core stability exercises with a Swiss ball in junior swimmers [35]. Thus, a Swiss-ball core strength training program can be used for improvements in muscle strength of the lower limb flexors (hamstrings), lower limb extensors (quadriceps), trunk flexor (abdominal), trunk extensor (lower back), endurance of the lower limb, lower back and abdominal muscles, flexibility of the lower back, and dynamic balance [36]. A 6-week program of Swiss ball training can be a suitable alternative to traditional floor exercises for improvements in core strength in collegiate athletes [37]. Balance, strength of the legs, and abdominal muscles were enhanced after both core stability dynamic and medicine ball training in male students of recreation health and physical education [38].