The effect of heavy-resistance core strength training on upper-body strength and power performance in national-level junior athletesa pilot study

Atle Hole Saeterbakken^1*Tor Einar Sandvikmoen²Erik Iversen³Thomas Bjørnsen⁴Nicolay Stien¹Vidar Andersen¹Suzanne Scott⁵Olaf Prieske⁶

• ¹Faculty of Education, Arts and Sports, Western Norway University of Applied Sciences, Sogndal, Norway
• ²Helsehuset Kristiansand, Kristiansand, Norway
• ³Olympiatoppen Sør, Kristiansand, Norway
• ⁴Department of Education and Sports Science, Faculty of Arts and Education, University of Stavanger, Stavanger, Norway
• ⁵School of Anatomy, Faculty of Health Sciences, University of Bristol, Bristol, England, United Kingdom
• ⁶Division of Exercise and Movement, University of Applied Sciences for Sports and Management Potsdam, Potsdam, Brandenburg, Germany

The concept of core strength refers to the ability of the core muscles to transfer, absorb and re-direct energy, and generate force/torque while providing proximal stability for distal mobility of the limbs. The aim of the present study was to examine the effects of an 8-week heavy-resistance core strength training (HR-CST) program on upper-body strength and power performance in young athletes. The secondary aim was to examine the role of sport-specific training background (kayak sprinters vs. swimmers) and sex (males vs. females). Eighteen national-level junior athletes (age: 17.1 ± 1.1 years, body height: 178 ± 7.8 cm, body mass: 70.2 ± 10.4 kg, 12 males, 6 females) competing in kayak sprint (n=6) and swimming (n=12) volunteered to participate. During the 8-week intervention period, half (i.e., 45 minutes) of the regular strength training program was replaced with HR-CST. Pre and post intervention, upper-body strength and power (i.e., maximal isokinetic stroke force [MIF] and power [MIP]) were tested by means of a maximal stroke test using a paddle ergometer. Additionally, peak (PP20) and average power (AP20) was determined in a 20-second all-out stroke test. Paired sample t-tests indicated that PP20 and AP20 were significantly improved by 12.8% (p<0.001, ES=0.30) and 11.9% (p<0.001, ES=0.28), respectively, following HR-CST. No statistical changes were observed in MIF and MIP (p>0.05, 0.19≤ES≤0.63). In conclusion, 8 weeks of HR-CST appears to be an effective means to improve upper-body strength and power performance in national-level junior kayak sprinters and swimmers. Our results suggest that a dynamic high-intensity core strength-training is a viable option for improving their performance in a periodized pre-season program and should be considered.