Fábio J. Lanferdini

Interferential therapy effect on mechanical pain threshold and isometric torque after delayed onset muscle soreness induction in human hamstrings

Abstract This study was undertaken to examine the acute effect of interferential current on mechanical pain threshold and isometric peak torque after delayed onset muscle soreness induction in human hamstrings. Forty-one physically active healthy male volunteers aged 18−33 years were randomly assigned to one of two experimental groups: interferential current group (n = 21) or placebo group (n = 20). Both groups performed a bout of 100 isokinetic eccentric maximal voluntary contractions (10 sets of 10 repetitions) at an angular velocity of 1.05 rad · s−1 (60° · s−1) to induce muscle soreness. On the next day, volunteers received either an interferential current or a placebo application. Treatment was applied for 30 minutes (4 kHz frequency; 125 μs pulse duration; 80−150 Hz bursts). Mechanical pain threshold and isometric peak torque were measured at four different time intervals: prior to induction of muscle soreness, immediately following muscle soreness induction, on the next day after muscle soreness induction, and immediately after the interferential current and placebo application. Both groups showed a reduction in isometric torque (P < 0.001) and pain threshold (P < 0.001) after the eccentric exercise. After treatment, only the interferential current group showed a significant increase in pain threshold (P = 0.002) with no changes in isometric torque. The results indicate that interferential current was effective in increasing hamstrings mechanical pain threshold after eccentric exercise, with no effect on isometric peak torque after treatment.

Joint kinematics assessment during cycling incremental test to exhaustion

Workload and experience in cycling have been suggested as factors influencing joint kinematics in cycling. The aims of our study were to (1) compare cyclists and non-cyclists lower limb kinematics and (2) to assess the effects of different workload levels on joint kinematics of cyclists and non-cyclists. Fifteen male athletes with experience in road cycling and triathlon competitions and fourteen male non-athletes volunteered to take part in the study. They performed an incremental test to exhaustion using their own bicycles (athletes) or a road bicycle set for their body dimensions (non-athletes). Right sagittal plane kinematics and gases exchanges were collected during the test. Ventilatory thresholds related workloads were defined for offline analysis of lower limb joint kinematics. Greater ankle range of motion was observed for athletes (17%) and non-athletes (25%) at maximal workload level compared to lower workload levels. Greater forward body position was observed for athletes (∼ 12%) and non-athletes (5-7%). Smaller hip flexion was observed for non-athletes compared to athletes (7%). Sub maximal workload level did not substantially affect lower limb joint kinematics. Similar lower limb joint motion between athletes and non-athletes suggests that changes in road cycling training may not result in different joint kinematics.

Effects of body positions on the saddle on pedalling technique for cyclists and triathletes

Abstract Cyclists usually change their body position on the saddle depending on the characteristics of the race. We compared the effects of cycling at three body positions on the saddle (preferred/self-selected, most forward, most backward) on pedalling technique for cyclists and triathletes. Twelve cyclists and nine triathletes performed four trials starting with the maximal aerobic workload, followed by three trials at the workload of their ventilatory threshold. Force applied on the right pedal via an instrumented pedal, lower limb kinematics via video and muscle activation via electromyography were recorded during all trials. Pedalling technique was quantified using total force applied on the pedal, pedal force effectiveness, activation of six lower limb muscles, joint angles and mechanical work at the ankle, knee and hip joints. Analyses using effect sizes showed no large effects from changes in position on the saddle for pedal forces, ankle joint work and ankle kinematics. There were large increases in knee joint angle and mechanical work and rectus femoris activation along with smaller hip work at the forward position on the saddle. Differences between cyclists and triathletes were not substantial. Effects of changes in saddle positions were limited to the hip and knee joints.

Water-Based Concurrent Training Improves Peak Oxygen Uptake, Rate of Force Development, Jump Height, and Neuromuscular Economy in Young Women

Abstract Pinto, SS, Alberton, CL, Cadore, EL, Zaffari, P, Baroni, BM, Lanferdini, FJ, Radaelli, R, Pantoja, PD, Peyré-Tartaruga, LA, Wolf Schoenell, MC, Vaz, MA, and Kruel, LFM. Water-based concurrent training improves peak oxygen uptake, rate of force development, jump height, and neuromuscular economy in young women. J Strength Cond Res 29(7): 1846–1854, 2015—The study investigated the effects of different intrasession exercise sequences on the cardiorespiratory and neuromuscular adaptations induced by water-based concurrent training in young subjects. Twenty-six healthy young women (25.1 ± 2.9 years) were placed into 2 water-based concurrent training groups: resistance before (RA, n = 13) or after (AR, n = 13) aerobic training. Subjects trained resistance and aerobic training during 12 weeks, 2 times per week performing both exercise types in the same training session. Peak oxygen uptake (V[Combining Dot Above]O2peak), rate of force development (RFD) obtained during an isometric peak torque knee extension protocol, jump height, and neuromuscular economy (normalized electromyography at 80% of pretraining knee extension isometric peak torque) in young women were determined. After training, there was a significant increase (p < 0.001) in both RA and AR in the V[Combining Dot Above]O2peak, with no differences between groups (7 vs. 5%). The maximal isometric knee extension RFD showed significant increases (p = 0.003) after training (RA: 19 vs. AR: 30%), and both groups presented similar gains. In addition, the countermovement jump height also increased (p = 0.034) after training (RA: 5% vs. AR: 6%), with no difference between groups. After training, there were significant improvements on vastus lateralis (p < 0.001) (RA: −13% vs. AR: −20%) and rectus femoris (p = 0.025) (RA: −17% vs. AR: −7%) neuromuscular economy, with no difference between groups. In conclusion, 12 weeks of water-based concurrent training improved the peak oxygen uptake, RFD, jump height, and neuromuscular economy in young women independent from the intrasession exercise sequence.

Comparison of kinetics, kinematics, and electromyography during single-leg assisted and unassisted cycling.

Abstract Bini, RR, Jacques, TC, Lanferdini, FJ, and Vaz, MA. Comparison of kinetics, kinematics, and electromyography during single-leg assisted and unassisted cycling. J Strength Cond Res 29(6): 1534–1541, 2015—To use single-leg cycling training for varying populations, it is important to understand whether a counterweight attached to the contralateral crank during single-leg cycling drills replicates the effects of the opposite leg in the ipsilateral leg. Therefore, we compared single-leg assisted cycling using a counterweight on the contralateral crank for joint kinetics, kinematics, and lower-limb muscle activation. Fourteen healthy nonathletes performed 2 bilateral cycling trials (240 ± 23 W and 90 ± 2 rpm) and 2 single-leg trials (120 ± 11 W and 90 ± 2 rpm) for measurements of pedal force, joint kinematics, and muscle activation of their right lower limb. For 1 single-leg trial, a custom-made adaptor was used to attach 10 kg of weight to the contralateral leg. Total force applied on the pedal, pedal force effectiveness, the mean joint angles and range of motion, mechanical work at the crank, hip, knee, and ankle joints, electromyography, pedaling cadence, and right crank mechanical work were assessed. Biceps femoris (87%), vastus lateralis (15%), rectus femoris (57%), tibialis anterior (57%), and gastrocnemius medialis (12%) activations were larger in the single-leg assisted trial compared with the bilateral trial. Lower total pedal force (17%) and increased index of effectiveness (16%) also indicate mechanical differences in single-leg cycling using a counterweight on the contralateral crank than conventional bilateral cycling. Single-leg assisted training should be used with caution because of potential differences in muscle recruitment and pedaling kinetics compared with bilateral cycling.

Cyclists and triathletes do not differ in muscle volume, muscle recruitment or pedal force effectiveness

BACKGROUND: Non-specific adaptation from training can elicit similar muscle volume and muscle activation between cyclists and triathletes which differ in comparison to non-athletes. OBJECTIVE: To compare muscle volume, muscle activation and pedal forces of cyclists, triathletes and non-athletes. METHODS: Twelve cyclists, ten triathletes and twelve non-athletes performed an incremental test to determine their maximal power output (POMAX). Quadriceps and triceps surae volume were estimated from ultrasound images taken at rest, while pedal forces and muscle activation were recorded at POMAX at 90 rpm. RESULTS: Quadriceps volume was larger in cyclists (∼22%, p < 0.04) and triathletes (∼40%, p < 0.01) compared to nonathletes. Higher activation of rectus femoris (∼55%, p = 0.01) and tibialis anterior (∼88%, p = 0.01) were observed for triathletes compared to non-athletes at the first quarter of the pedaling cycle. Triathletes also showed higher activation for tibialis anterior than cyclists (∼68%, p = 0.03) at the first quarter. Non-athletes applied greater force on the pedal compared to triathletes at the first quarter (∼42%, p < 0.01). Pedal force effectiveness was higher for athletes (37–44%, p < 0.02) compared to nonathletes at the fourth quarter. CONCLUSIONS: Similar muscle volume and muscle activation between cyclists and triathletes may be related to a similar training volume supporting differences relative to non-athletes.