‍Background and Purpose 

Complex training involves using combinations of strength and ballistic/plyometric exercises. The strength exercise typically involves the use of a barbell or dumbbell, but the authors suggested that flywheel training could be particularly useful for this purpose. To test this idea, they compared the effects of a flywheel-based vs barbell-based complex training program in collegiate volleyball athletes.  

Methods 

14 NCAA Division 1 volleyball players were randomly assigned to perform 8-weeks of complex training which included either flywheel squats (n=7) or Smith Machine squats (n=7).  Three sessions were completed per week, and each session included 3 sets of 8 reps of the squat exercise and 3 sets of 12 drop jumps. Measures of muscle thickness, half-squat strength, and vertical jump performance (countermovement jump, squat jump, three-step approach jump) were measured before and after the 8-week intervention period.  

Results 

• Both groups increased muscle thickness, but the improvements were greater for the flywheel group (6% vs 3%).  

• Both groups improved their half-squat strength, but the improvements were greater for the flywheel group (22.5% vs 12.4%).  

• Squat jump height (11% vs 3%) and peak power (23% vs 7%) improved to a greater degree in the Smith Machine compared to the flywheel group.  

• But the flywheel group had significant improvements in countermovement jump and power and approach jump height and power, which were not seen in the barbell group.  

Key Takeaways 

When comparing complex training using either flywheel or Smith Machine squats, there were several key differences. The flywheel group had greater improvements in half-squat strength, quadriceps muscle thickness, and performance in both countermovement and three-step approach jumps. The Smith Machine group had greater gains in squat jump performance. The authors discussed how the eccentric loading offered by flywheel squats likely resulted in greater improvements in muscle thickness and in the two jumps that rely on the stretch shortening cycle. In contrast, squat jumps have no eccentric component or stretch shortening cycle component, which may explain why flywheels had less of an influence on this test. Overall, the authors suggested that flywheel training combined with plyometrics may be an advantageous way for volleyball players to train to improve their athletic performance, strength, and muscle size.  

• The eccentric loading and stretch shortening cycle component of max effort flywheel half-squats may be particularly useful for improving performance in movements underpinned by the SSC such as countermovement and approach jumps. Notably, these are the types of movements that are common within volleyball and many other sports.  

• The results also suggested that flywheel training was useful for increasing lower body strength and hypertrophy, suggesting it is a useful means of driving valuable neuromuscular adaptations that underpin sport performance.