You are correct. The athletes are also higher trained than i originally imagined. Fitness was 2.4 timing around 7.9 mins on avg before the test. Just 6 weeks plyo training as intervention.....not months etc.
The key takeaways got typo i think......is not 23.9 but 3.9% avg improvement. (combined value between men and women). Some improved much more than others also, coz it ranged from 9.9% improvement to just 1.1% improvement. Though, still not too shabby........shd translate to 5K as well.
It's very good money that can be tapped coz the plyo training is not difficult or time consuming at all, dosage is 2x per week. Actually if office got quiet room, can even do there after lunch.....like how some of us are doing as well.
For me actually i had been doing already for more than a year (similar dosage and frequency, sometimes just 1x per week actually), but just wondering how much is it aiding my 3k, 5k or even the occasional 6-8k. At least now i have an answer. But then for me a bit risky, i dont warm up one.

But so far so good no issue in my grand scheme of things.
For 2.4k, the men were getting improvements in the 18s range on avg.
Might seem not a lot, but it is not insignificant in the 7-8 mins fit zai range.
I got the details from another link :
https://journals.lww.com/nsca-jscr/..._plyometric_training_on_endurance_and.13.aspx
Subjects
For the intervention, a group of competitive middle- and long-distance runners (22 menand 14 women; 22.1 ± 2.7 years of age) were recruited. They had a minimum of 2 years of competitive experience at national and international level, with personal best times that ranged from 3:50 and 4:27 (minutes:seconds) at the 1500 m (men and women, respectively) to 2:32 and 2:52 (hours:minutes) at the Marathon (men and women, respectively). Subjects had no explosive strength training experience in the last 6 months. Athletes completed (mean ±
SD) 6.94 ± 1.8 running endurance training units per week, for a total running weekly volume of 67.2 ± 18.9 km (TG 64.7 ± 18.8 km; CG 70.0 ± 19.3 km; no significant difference between groups), where high intensity interval training bouts of long (i.e., >1 minuteute) duration were the preferred training method.
This training load was added to their respective competitive schedule. Although the V[Combining Dot Above]O2max was not measured, the whole group of athletes (including women) underwent a 2.4-km time trial running performance test in a mean of 7.9 ± 0.8 minutes before intervention, suggesting a high level of fitness in comparison with previous reports (28,34–36).
2.4-km Running Endurance Test
This was the only test that took place outdoors. The wind velocity at all times was between 5.5 to 9.9 km·h−1, the relative humidity was 50–66%, and the temperature was 13–14° C (Chilean Meteorological Service, Santiago, Chile). Athletes were instructed to run for maximal performance. The head coach took results as a guide to select athletes for competition, so motivation was considered maximal. Athletes individually completed 6 laps in a 400-m outdoor polyurethane track. Because the middle- and long-distance runners recruited for the study compete in different distances, we choose a standard distance for all athletes (2.4 km), as all of them were accustomed to this test as part of their annual general fitness assessment battery. For the specific warm-up, 2 submaximal laps around the track were completed, and 4 minutes later athletes had 1 maximal attempt to complete the test.
After 6 weeks of treatment, a significant reduction was observed in 2.4 km (
p < 0.01) and 20 m (
p < 0.01) time test in the TG. Also, after training, the TG shows a significant difference in 2.4 km (
p < 0.05) and 20 m (
p < 0.05) time test in comparison with the CG (
Table 1).
Treatment
The plyometric training intervention period lasted for 6 weeks, as this time frame had shown to be adequate for significant endurance related adaptations (28,36,37), and was carried out during the initial part of the competition season. No reduction in running endurance training volume was applied to the TG (i.e., the TG and CG kept their usual volume of running endurance training during the intervention). The athletes were instructed to maintain their usual dietary habits for the entire duration of the study and they did not perform plyometric exercise during intervention (other than the planned explosive exercises for the TG). Before the initiation of the plyometric training period, the athletes were instructed as to the proper execution of all the exercises to be done during this period. The plyometric training took place 2 days per week (with at least 48 hours of rest between sessions) because this training frequency had been shown to induce significant explosive-related and endurance-related adaptations in endurance athletes (36), with significant superior efficiency as compared with higher training frequencies (6). Plyometric training sessions lasted less than 30 minutes and were completed immediately before the endurance training. Standard warm-up (i.e. 5 minutes of submaximal running and several displacements, 20 submaximal vertical jumps and 10 submaximal longitudinal jumps) was used before the main part of the training session. The plyometric exercises consisted only of DJs (bounce drop jumps), with a total of 60 DJs per session (2 series of 10 jumps from a 20 cm box, 2 series of 10 jumps from a 40 cm box, and 2 series of jumps from a 60 cm box) for the TG. This volume has been used in previous studies, obtaining significant positive results (4,6). The rest period between repetitions was of 15 seconds, as previously recommended (31), and between series was of 2 minutes. The control group did not perform plyometric training and underwent the same testing protocols as the TG.
Athletes from the TG used the same surface (i.e., wooden floor) to complete all the plyometric training sessions. Athletes were instructed to place their hands on their hips and step off the platform with the leading leg straight to avoid any initial upward propulsion, ensuring a drop height of 20, 40, and 60 cm. They were instructed to jump with maximal intensity for maximal height and minimum contact time in every jump. These instructions were intended to maximize explosive strength requiring fast SSC. A researcher was always present during training sessions, motivating athletes to give their maximum effort in each jump.