Jefferson Fagundes Loss

Bio: Jefferson Fagundes Loss is an academic researcher from Universidade Federal do Rio Grande do Sul. The author has contributed to research in topics: Lactate threshold & Electromyography. The author has an hindex of 12, co-authored 24 publications receiving 384 citations. Previous affiliations of Jefferson Fagundes Loss include Universidade do Vale do Rio dos Sinos.

Effective force and economy of triathletes and cyclists

Abstract: The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy.

Comparing the lactate and EMG thresholds of recreational cyclists during incremental pedaling exercise

Abstract: The purpose of this study was to determine the validity of using the electromyography (EMG) signal as a noninvasive method of estimating the lactate threshold (LT) power output in recreational cycl...

Electromyography for Assessment of Pain in Low Back Muscles

Abstract: Background and Purpose: Pain is currently evaluated with “subjective” methods (eg, patient self-report). This study aimed to test whether fatigue indexes are able to accurately discriminate between subjects with and subjects without low back pain. Subjects: Sixty subjects separated into 2 groups—a group with low back pain (n=30) and a group without low back pain (n=30)—participated in this study. Methods: Electromyographic (EMG) and force data were obtained during a muscle fatigue test. The same test was repeated to monitor recovery. Linear regression analysis was used to obtain fatigue indexes. Results: Subjects with pain produced significantly lower force values than those without pain. The use of fatigue indexes and force values permitted accurate classification in 89.5% of cases. Discussion and Conclusion: The results confirm that subjects with pain show early myoelectrical manifestations of muscle fatigue and that EMG can be a useful tool in the evaluation of low back pain.

Exercise and Sport Science

Abstract: Whether your interest is in teaching, coaching, fitness, or management, the Department of Exercise and Sport Science is committed to helping each student achieve his or her maximum potential. Each student is assigned a faculty adviser to assist with academic and career decisions. Our highly acclaimed “learn by doing” reputation is further enhanced by providing students with hands-on educational experiences in their area of choice. While maintaining a strong tradition in activities and the sciences, the department also emphasizes innovative programs and activities designed to maintain healthy, active life styles.

Effects of Kinesio® Tape in low back muscle fatigue: randomized, controlled, doubled-blinded clinical trial on healthy subjects.

Abstract: BACKGROUND: Muscle fatigue of the trunk extensor musculature plays a considerable role in chronic low back pain (LBP). The underlying physiology of fatigue is complex and not fully understood. The Kinesio Taping (KT) supports damaged structures while allowing mobility and at the same time may influence some of the mechanisms associated with muscle fatigue such as blood flow and proprioception. OBJECTIVE: The aim of this study is to determine the influence of KT on the resistance to fatigue of the lumbar extensor musculature in a sample of young healthy subjects. METHODS: A randomized, controlled, doubled-blinded clinical trial was conducted. Ninety nine healthy subjects were randomized in to the three arms of the study Kinesio Tape (KT), placebo (P) and control (C). Directly after application of KT we measured lumbar extensor musculature endurance with the Biering-Sorensen test. Subjects and researchers were blinded to the intervention. Time achieved (seconds) was compared between groups with one-way ANOVA with confidence intervals of 95%. RESULTS: There were significant differences between the time achieved in the KT group versus the control group ( p< 0.05). The placebo group performed better than the control group but worse than the KT group, these were not significant in either case. CONCLUSIONS: KT appears to improve the time to failure of the extensor muscle of the trunk obtained using the BieringSorensen test. These findings suggest that KT influences processes that lead to muscle fatigue and that KT could be effective in the management of LBP.

Saddle height effects on pedal forces, joint mechanical work and kinematics of cyclists and triathletes

Abstract: The effects of saddle height on pedal forces and joint kinetics (e.g. mechanical work) are unclear. Therefore, we assessed the effects of saddle height on pedal forces, joint mechanical work and kinematics in 12 cyclists and 12 triathletes. Four sub-maximal 2-min cycling trials (3.4 W/kg and 90 rpm) were conducted using preferred, low and high saddle heights (±10° knee flexion at 6 o'clock crank position from the individual preferred height) and an advocated optimal saddle height (25° knee flexion at 6 o'clock crank position). Right pedal forces and lower limb kinematics were compared using effect sizes (ES). Increases in saddle height (5% of preferred height, ES=4.6) resulted in large increases in index of effectiveness (7%, ES=1.2) at the optimal compared to the preferred saddle height for cyclists. Greater knee (11-15%, ES=1.6) and smaller hip (6-8%, ES=1.7) angles were observed at the low (cyclists and triathletes) and preferred (triathletes only) saddle heights compared to high and optimal saddle heights. Smaller hip angle (5%, ES=1.0) and greater hip range of motion (9%, ES=1.0) were observed at the preferred saddle height for triathletes compared to cyclists. Changes in saddle height up to 5% of preferred saddle height for cyclists and 7% for triathletes affected hip and knee angles but not joint mechanical work. Cyclists and triathletes would opt for saddle heights <5 and <7%, respectively, within a range of their existing saddle height.

Effects of saddle height, pedaling cadence, and workload on joint kinetics and kinematics during cycling.

Abstract: Context: It is not clear how noncyclists control joint power and kinematics in different mechanical setups (saddle height, workload, and pedaling cadence). Joint mechanical work contribution and kinematics analysis could improve our comprehension of the coordinative pattern of noncyclists and provide evidence for bicycle setup to prevent injury. Objective: To compare joint mechanical work distribution and kinematics at different saddle heights, workloads, and pedaling cadences. Design: Quantitative experimental research based on repeated measures. Setting: Research laboratory. patients: 9 healthy male participants 22 to 36 years old without competitive cycling experience. Intervention: Cycling on an ergometer in the following setups: 3 saddle heights (reference, 100% of trochanteric height; high, + 3 cm; and low, − 3 cm), 2 pedaling cadences (40 and 70 rpm), and 3 workloads (0, 5, and 10 N of braking force). Main Outcome Measures: Joint kinematics, joint mechanical work, and mechanical work contribution o...