Search

Background: Laboratory assessment of maximal oxygen uptake ( V ˙ O 2 max) is physically and mentally draining for the athlete and requires expensive laboratory equipment. Indirect measurement of V ˙ O 2 max could provide a practical alternative to laboratory testing. Purpose: To examine the relationship between the maximal power output (MPO) in an individualized 7 × 2-minute incremental test (INCR-test) and V ˙ O 2 max and to develop a regression equation to predict V ˙ O 2 max from MPO in female rowers. Methods: Twenty female club and Olympic rowers (development group) performed the INCR-test on a Concept2 rowing ergometer to determine V ˙ O 2 max and MPO. A linear regression analysis was used to develop a prediction of V ˙ O 2 max from MPO. Cross-validation analysis of the prediction equation was performed using an independent sample of 10 female rowers (validation group). Results: A high correlation coefficient (r =.94) was found between MPO and V ˙ O 2 max. The following prediction equation was developed: V ˙ O 2 max (mL·min−1) = 9.58 × MPO (W) + 958. No difference was found between the mean predicted V ˙ O 2 max in the INCR-test (3480 mL·min−1) and the measured V ˙ O 2 max (3530 mL·min−1). The standard error of estimate was 162 mL·min−1, and the percentage standard error of estimate was 4.6%. The prediction model only including MPO, determined during the INCR-test, explained 89% of the variability in V ˙ O 2 max. Conclusion: The INCR-test is a practical and accessible alternative to laboratory testing of V ˙ O 2 max. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to examine the test−retest reliability in lower limb muscle strength and rate of torque development (RTD) using isokinetic dynamometry in adults with obesity, with a body mass index (BMI) ≥ 35 kg/m2. Method: Thirty‐two adults with a BMI of 43.8 ± 6.6 kg/m2 eligible for bariatric surgery were enroled in the study. Isokinetic and isometric knee extensor (KE) and flexor (KF) strength were assessed in an isokinetic dynamometer (Biodex 4) during three test sessions separated by 3−7 days. Results: There were no statistical differences in peak KE and KF torque for any test modalities between sessions. Intraclass correlation (ICC) was 0.91−0.94 between sessions 1 and 2 and 0.94−0.97 between sessions 2 and 3. Standard error of measurement (SEM%) and coefficient of variation (CV) ranged across test sessions from 4.3% to 7.3%. KE RTD showed high test−retest reliability following familiarization, with ICC, CV and SEM% values ranging from 0.84 to 0.90, 13.3%−20.3% and 14.6%−24.9%, respectively. Conclusion: Maximal lower limb muscle strength measured by isokinetic dynamometry showed excellent test−retest reliability manifested by small measurement errors and low CV. Reliability was slightly improved by including a familiarization session. KE RTD but not KF RTD demonstrated high test−retest reliability following familiarization. The present data indicate that isokinetic dynamometry can be used to detect even small changes in lower limb muscle strength in adults with obesity. [ABSTRACT FROM AUTHOR]

Purpose: To examine the relationship between the maximal power output (MPO) in an individualized 7 x 2-minute incremental (INCR) test, average power in a 2k (W2k) rowing ergometer test, and maximal oxygen uptake (VO2max) and to develop a regression equation to predict VO2max. Methods: A total of 34 male club rowers (age 18-30 y) performed a 2k and an INCR test in a Concept2 rowing ergometer to determine and compare MPO, W2k, and VO2max. Results: No significant difference was found between VO2max measured during INCR or 2k test (P = .73). A very high correlation coefficient (r = .96) was found between MPO and VO2max and between W2k and VO2max (r = .93). Linear regression analyses were developed for predicting VO2max from MPO: (1) VO2max (mL·min-1) = 11.49 x MPO + 810 and VO2max from W2k: (2) VO2max = 10.96 x W2k + 1168. Cross-validation analyses were performed using an independent sample of 14 rowers. There was no difference between the mean predicted VO2max in the INCR test (4.41 L·min-1) or the 2k test (4.39 L·min-1) and the observed VO2max (4.40 L·min-1). Technical error of measurement was 3.1% and 3.6%, standard error of estimate was 0.136 and 0.157 mL·min-1, and validation coefficients (r) were .95 and .94 using Equation (1) and (2), respectively. Conclusion: A prediction model only including MPO or W2k explains 88% to 90% of the variability in VO2max and is suggested for practical use in male club rowers. [ABSTRACT FROM AUTHOR]

This paper aimed to examine the acute effect of low-load (LL) exercise with blood-flow restriction (LL-BFR) on microvascular oxygenation and muscle excitability of the vastus medialis (VM) and vastus lateralis (VL) muscles during a single bout of unilateral knee extension exercise performed to task failure. Seventeen healthy recreationally resistance-trained males were enrolled in a within-group randomized cross-over study design. Participants performed one set of unilateral knee extensions at 20% of one-repetition maximum (1RM) to task failure, using a LL-BFR or LL free-flow (LL-FF) protocol in a randomized order on separate days. Changes in microvascular oxygenation and muscle excitability in VL and VM were assessed using near-infrared spectroscopy (NIRS) and surface electromyography (sEMG), respectively. Pain measures were collected using the visual analog scale (VAS) before and following set completion. Within- and between- protocol comparisons were performed at multiple time points of set completion for each muscle. During LL-BFR, participants performed 43% fewer repetitions and reported feeling more pain compared to LL-FF (p<0.05). Normalized to time to task failure, LL-BFR and LL-FF generally demonstrated similar progression in microvascular oxygenation and muscle excitability during exercise to task failure. The present results demonstrate that LL-BFR accelerates time to task failure, compared with LL-FF, resulting in a lower dose of mechanical work to elicit similar levels of oxygenation, blood-pooling, and muscle excitability. LL-BFR may be preferable to LL-FF in clinical settings where high workloads are contraindicated, although increased pain experienced during BFR may limit its application. Highlights Compared to free flow (FF), neuromuscular fatigue mechanisms are accelerated during blood flow restricted (BFR) training. This can be observed as changes in microvascular oxygenation and muscle excitability occurring at a ∼43% faster mean rate during BFR compared to FF. BFR exercise seems to elicit the same level of neuromuscular fatigue as FF training within a shorter timeframe. This reduces total joint load and may be especially helpful in cases where high training volumes may be contraindicated (e.g. recovering from a sports injury or orthopedic surgery). [ABSTRACT FROM AUTHOR]