• Low Body Fat Does Not Influence Recovery after Muscle-Damaging Lower-Limb Plyometrics in Young Male Team Sport Athletes

      Fernandes, John F. T.; email: jfmtfernandes@hotmail.co.uk; Lamb, Kevin L.; orcid: 0000-0003-4481-4711; email: k.lamb@chester.ac.uk; Twist, Craig; orcid: 0000-0001-6168-0378; email: c.twist@chester.ac.uk (MDPI, 2020-11-05)
      Aim: This study assessed the influence of fat mass to fat-free mass ratio (FM:FFM) on recovery from plyometric exercise. Method: After assessment of body composition, 20 male team sport players (age 20.7 ± 1.1 years; body mass 77.1 ± 11.5 kg) were divided into low- (n = 10; 0.11 ± 0.03) and normal- (n = 10; 0.27 ± 0.09) fat groups based on FM:FFM ratio. Thereafter, participants completed measurements of knee extensor torque at 60 and 240°∙s−1, countermovement jump flight time, plasma creatine kinase (CK) activity and perceived muscle soreness (VAS) before and at 0, 24 and 48 h after 10 × 10 maximal plyometric vertical jumps. Results: Evidence of muscle damage was confirmed by alterations in VAS, peak torque at 60 and 240°∙s−1 and flight time at 0, 24 and 48 h after plyometric exercise (P 0.05). CK was increased at 0 and 24 h (P 0.05) but returned to baseline values by 48 h. No time by group effects were observed for any of the dependent variables (P > 0.05). Conclusion: The current findings indicate that while muscle damage was present after plyometric exercise, the magnitude was similar across the two body composition groups. Applied practitioners can allow for a similar recovery time after plyometric exercise in those with low and normal body fat.
    • Prediction of One Repetition Maximum Using Reference Minimum Velocity Threshold Values in Young and Middle-Aged Resistance-Trained Males

      Fernandes, John F. T.; email: jfmtfernandes@hotmail.co.uk; Dingley, Amelia F.; email: amelia.dingley@hartpury.ac.uk; Garcia-Ramos, Amador; orcid: 0000-0003-0608-8755; email: amagr@ugr.es; Perez-Castilla, Alejandro; orcid: 0000-0001-5535-2087; email: alexperez@ugr.es; Tufano, James J.; orcid: 0000-0001-8325-0344; email: tufano@ftvs.cuni.cz; Twist, Craig; orcid: 0000-0001-6168-0378; email: c.twist@chester.ac.uk (MDPI, 2021-05-07)
      Background: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. Methods: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20–80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. Results: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. Conclusion: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.