ECSS Paris 2023: OP-AP05
INTRODUCTION: The aims of this study were to (i) compare the acute physical fitness changes after 6-weeks of flywheel resistance training when using a flywheel cluster-set (FCS) and flywheel straight-set (FSS) protocol and (ii) to monitor the effect of set configuration on flywheel training variable (mean/ peak power outputs and eccentric overload) progression during the intervention period. METHODS: Twenty-four amateur male field sport athletes (n=24) were randomly allocated into one of two groups (FCS and FSS). Participants underwent pre- and post-intervention testing for 20m linear sprints (Including a 5m sprint interval), countermovement jump (CMJ) performance (height, force and velocity), change of direction (5-10-5) time, and maximal isometric mid-thigh pull (IMTP) strength (peak vertical force (N)). During the intervention, both FCS and FSS groups performed two weekly sessions of quarter-squats and Romanian deadlifts using 0.050 kg.m2 inertial load. The FCS group employed cluster set blocks of three repetitions (3x3x3), with 30-second intra-set rest periods allocated between cluster blocks per session (Ryan et al., 2024b) whereas the FSS group performed four sets of nine repetitions per session. The kmeter apparatus was used to record training variables within sessions and monitor progression of flywheel training performance during the intervention period. RESULTS: Performance measures were found to be reliable (ICC= 0.876-0.985; CV%= 0.98%-4.82%). A group by time interaction showed a significant (p=0.043) difference for the 5m linear sprint distance in favour of the FCS group. Within group analysis for pre- to post-testing for the FCS group showed improvements for 5m (p=0.016; effect size [ES]=0.82) and 20m sprint time (p=0.016; ES=0.74); COD time (p<0.001; ES=0.34-0.75) and CMJ performance (height; p<0.001, force; p=0.012, velocity; p=0.025; ES=0.25-0.45). Similarly, the FSS group reported improvements in COD time (p≤0.050; ES=0.47-0.49) and CMJ performance (height; p<0.001, force; p=0.030; ES=0.35-0.53). Additionally, both intervention groups observed no significant improvements in IMTP strength (ES=0.045-0.19). CONCLUSION: The findings support the usability of both flywheel training protocols to enhance field sport athletic performance. However, the FCS group experienced greater improvements in performance, providing an alternative option for flywheel training through the use of cluster sets.
Read CV Shane RyanECSS Paris 2023: OP-AP05
INTRODUCTION: The measurement of velocity through accelerometers or linear encoders has become a common practice in resistance training. As peak velocity is dependent to the total impulse expressed during a contraction, practitioners have recently focused on time to peak velocity as a complementary measure, which is thought to better reflect dynamic rate of torque development (RTD). Consequently, the aim of this work is to understand the behavior of this metric at different velocity conditions and its relationship with dynamic RTD and muscle activation. METHODS: Sixty-four young adults performed two isometric maximal voluntary contractions (MVC) and an incremental load test on a single-leg isoinertial leg extension to obtain their individual torque-velocity relationship and to measure peak torque, peak velocity, time to peak velocity and RTD for each load. The root mean square (RMS) of high-density surface electromyography (HDsEMG) recorded from the vastus lateralis and medialis was quantified in the first 50 ms of each contraction. Torque and EMG signals of dynamic contractions were normalised by the corresponding values obtained during MVC. Linear hierarchical regression analysis was used to assess the relationship between time to peak velocity (dependent variable), peak velocity and peak RTD as fixed factors. A second model was performed using peak velocity and RMS as fixed factors. Each analysis was performed accounting for repetition’s peak torque and considering the intercept and slope of peak velocity of each subject as a random effect. RESULTS: As expected, time to peak velocity was principally affected by peak velocity (F = 461.6, β = -7.4 x 10^-1, η2 = 0.80, p < 0.001) but also influenced by peak RTD (F = 141.3, β = - 1.3 x 10^-3, η2 = 0.18, p < 0.001). In the second model, peak velocity retained its primary role in determining time to peak velocity (F = 475.2, β = -7.5 x 10^-1, η2 = 0.77, p < 0.001) with a significant effect of RMS (F = 91.9, β = - 9.7 x 10^-3, η2 = 0.13, p < 0.001). In each analysis, the independent influence of peak torque was minimal (η2 ≤ 0.01). CONCLUSION: We support the theoretical basis for using time to peak velocity as an indirect indicator of the rate of torque development during dynamic resistance training contractions. This is further reinforced by the correlation between early muscle excitation (first 50 ms), which is widely recognized as a key factor influencing explosive contractions, and time to peak velocity.
Read CV Ludovico GrossioECSS Paris 2023: OP-AP05
INTRODUCTION: The use of multi-joint or single-joint resistance exercises is an effective method to increase muscle strength and mass. Yet, it remains unclear if the use of a multi-joint or a single-joint exercise, might result in different loss rates of these adaptations during a detraining period. The purpose of this study was to investigate the effect of 8 weeks detraining on muscle strength and mass of lower extremities after 8 weeks systematic resistance training with either multi-joint or single-joint exercises. METHODS: Fourteen young moderately trained women (height 173±6cm, mass 62±10kg), with no experience in systematic resistance training, followed 8 weeks of unilateral lower extremities’ strength training, in which one leg trained with multi-joint exercise (leg press; LP) and the other with single joint exercise (knee extension; KE). The training protocol involved 2 sessions per week, 4 sets X 6 repetitions at, 80% of maximal strength for both training interventions. After 8 weeks of training, participants completely abstained from training for another 8 weeks. Unilateral maximum strength (1-RM) in LP and KE, quadriceps’ muscle cross sectional area (CSA) at 2 different sites of the thigh length (40%, 60%) and vastus lateralis (VL) thickness (via ultrasonography) were evaluated before training (T1), at the end of systematic training (T2) and at the end of detraining (T3). RESULTS: Unilateral 1-RM strength increased significantly (LP: 36.5±11.5% and KE: 28.3±14.8%, respectively, p<0.05) after training, with no difference between interventions (p>0.05). Quadriceps muscle CSA increased at 40% (LP: 10.2±3.6% and KE: 8.2±3.4%, p<0.05) and at 60% of thigh length (LP: 11.2±4.5% and KE: 7.1±3.2%, p<0.05) with significant differences between interventions, p<0.05). VL thickness increased significantly (LP: 8.4±4.5% and ΚΕ: 5.6±5.4%, p<0.05) with significant differences between interventions, p<0.05) after systematic training. Unilateral 1RM strength decreased between T2-T3 (LP: -11.2±6.3% and KE: -16.8±6.5%, p<0.05) with significant difference between interventions, p<0.05). Quadriceps’ muscle CSA at 40% of thigh length (LP: -5.9±2.1% and KE: -6.3±3.4%, p<0.05) and at 60% of thigh length (LP: -7.0±2.8% and KE: -4.8±2.1%, p<0.05), as well as VL thickness (LP: -4.9±3.0% and ΚΕ: -3.2±3.6%, p<0.05) decreased significantly between T2-T3, but with no difference between interventions. CONCLUSION: These findings indicate that leg press and knee extension resulted in similar increases in 1-RM. On the contrary, the LP led to larger increases in quadriceps muscle mass in comparison to the KE. However, after 8 weeks of detraining, a comparable reduction in muscle mass is anticipated regardless of the type of exercise that was previously implemented. Therefore, the use of a mutli-joint resistance exercise is a more effective way to increase muscle mass, yet detraining has a similar effect in muscle mass reduction regardless of the type of exercise used.
Read CV Thomas MpampoulisECSS Paris 2023: OP-AP05