Post-activation potentiation (PAP) is acknowledged as a short-term enhancement in muscle strength and power after performing a high intensity conditioning activity. It has been demonstrated that such high-intensity exercises during warm-up routines may improve performance in speed and power events.
Post-activation potentiation has been documented in different activities and sports. In swimming, dry-land exercises induced PAP in peak vertical and horizontal force in the starting block, but not in the freestyle performance. As it has been demonstrated that conditioning activities should be similar to the desired task, the lack of PAP in the water might be a consequence of the exercise selection for a conditioning activity (pull-ups and jumps), which did not resemble the complexity of swimming motions. Thus, it is conceivable that an in-water strength exercise might serve as a possible more specific trigger for PAP in swimming.
Hand paddles and parachutes are two of the most-used implements to increase specific strength in swimming. The artificial enlargement of hands’ surface area provided by paddles, and the additional drag created by parachutes, lead swimmers to generate a greater propulsive force in each stroke without meaningful changes in trajectory, pitch, and sweepback angles of the hand. The use of these implements may represent a more specific stimulus to induce PAP effects on swimming.
The objectives of this study were to investigate if an in-water strength training set performed with hand paddles and parachute would induce PAP in swimming propulsive force, and whether a swimmer’s force level affects a post-activation potentiation response.
Eight well-trained national competitive swimmers (age: 18.4 ± 1.3 years; IPS = 796 ± 56 points), 5 males (body mass: 73.3 ± 4.6 kg; height: 1.82 ± 0.02 m; fat percentage: 9.3 ± 3.9 %) and 3 females (body mass: 60.6 ± 9.2 kg; height: 1.69 ± 0.01 m; fat percentage: 19.3 ± 4.2 %), took part in this study. They were front-crawl specialists and experienced with in-water strength training.
After the warm-up, swimmers performed a tethered swimming test (which consisted of a 10-s maximal swimming effort with self-selected stroke rate) twice before (PRE1 and PRE2) and twice after (POST1 and POST2) a conditioning activity. The conditioning activity consisted of 8 maximum efforts of 12.5 m starting every 2.5 min using both hand paddles (245 cm2) and parachute (400 cm2).
PRE1 and PRE2 tests were used to investigate whether the test itself could induce PAP and were separated by 4 min. POST1 and POST2 were performed 2.5 and 6.5 min after the conditioning activity, respectively. POST1 and POST2 were used to assess possible PAP over time.
Propulsive force was evaluated by means of a fully tethered swimming system composed by a load cell with 4 strain gages and 2 000 N of maximum capacity. The data were used to assess peak force (the highest force value between 2 consecutive minimum force values), impulse (the force applied in a given time), and the rate of force development (RFD).
The in-water strength training set negatively affected peak force and impulse, but had no effect on RFD. Indeed, the pairwise comparison revealed a lower peak force in POST1 (p = 0.02), and also impulse in both POST1 (p = 0.007) and POST2 (p = 0.004) compared to PRE. There was no difference between POST1 and POST2.
The lack of PAP’s beneficial effects may be attributed to certain characteristics of the conditioning activity (i. e., high number of repetitions, short rest interval) which induced a greater fatigue, consequently, and masked the effects of PAP.
Even though most subjects decreased force-time curve parameters after the conditioning activity, positive correlations were found between both peak force and impulse, and the PRE-POST percent changes for peak force (r = 0.71 and 0.76, respectively) and RFD (r = 0.79 and 0.76, respectively). This indicates that swimmers with lower peak force and impulse were also those with the greater reduction in tethered swimming performance. Due to a same absolute resistance (same size of paddles and parachute), a higher relative intensity in swimmers with lower initial force levels may have resulted in greater fatigue.
The findings indicate that the current hand paddles and parachute-based conditioning activity should not be used before main competitive events, at least for swimmers with the present competitive and/or propulsive force levels.
Barbosa AC et al. (2015) Post-activation Potentiation in Propulsive Force after Specific Swimming Strength Training. Int J Sports Med.