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• A 3-min All-out Cycling Test Is Sensitive to a Change in Critical Power

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  A 3-min All-out Cycling Test Is Sensitive to a Change in Critical Power

  Author(s)

  Anni VanHatalo, Jonathan H. Doust, Mark Burnley

  Date

  2008-12-15

  Source

  Medical Science in Sports and Exercise. Volume 40., No. 9, pp. 1693–1699, 2008

  Purpose: The aim of this investigation was to test the hypothesis that a 3-min
  all-out cycling test would detect a change in critical power (CP) after a 4-wk interval training intervention. Methods: Nine habitually active subjects completed a ramp test, two 3-min all-out tests to establish the end power (EP) and the work done above EP (WEP), and three predicting trials to establish CP and W’ using the work–time model (W = CPt + W’). After 12 supervised high-intensity interval training sessions over 4 wk, subjects repeated the testing procedures. Results: The CP increased in all subjects after training (pretraining: 230 ± 53 W; posttraining: 255 ± 50 W; t8= 7.47, P G 0.001), with no statistically significant effect on the W’ (pretraining: 17.2 ± 4.2 kJ; posttraining: 15.5 ± 3.8 kJ; t8= 2.03, P = 0.08). The all-out test EP was increased after training from 225 ± 52 W to 248 ±46 W (t8= 6.26, P < 0.001). The EP and CP estimates before and after training were not different and were highly correlated
  (pretraining: r = 0.96, P < 0.001; posttraining: r = 0.95, P < 0.001). In addition, the increase in EP was correlated with (r = 0.77, P =0.016) and not different from (t8= 0.60, P = 0.57) the increase in CP. There was no change in the WEP from pretraining to posttraining (t8= 1.89, P = 0.10). Conclusions: The present study shows that the 3-min all-out test closely estimates CP across a wide range of aerobic fitness and is sensitive to training-induced changes in CP.

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• Acute effects of small changes in crank length on gross efficiency and pedalling technique during submaximal cycling.

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  Acute effects of small changes in crank length on gross efficiency and pedalling technique during submaximal cycling.

  Author(s)

  Ferrer-Roca, Rivero-Palomo, Ogueta-Alday, Rodríguez-Marroyo, García-López

  Date

  2017-07-01

  Source

  Journal of Sports Sciences

  The main purpose of this study was to assess the acute effects of small changes in crank length (assumable by competitive cyclists) on metabolic cost and pedalling technique during submaximal cycling. Twelve amateur road cyclists performed three sets of submaximal pedalling (150, 200 and 250 W) at a constant cadence (91.3 ± 0.8 rpm) in a randomised order with three commonly used crank lengths, preferred (172.5-175 mm), +5 mm and -5 mm. Energy cost of pedalling, kinetic and kinematic variables were simultaneously registered. Changes in crank length had no significant effect on heart rate (144 ± 13, 145 ± 12 and 145 ± 13 bpm, respectively) and gross efficiency (GE) (20.4 ± 2.1, 20.1 ± 2.2 and 20.3 ± 2.4%, respectively). A longer crank induced a significant (P < 0.05) reduction of positive impulse proportion (PIP) (0.9-1.9%) due to a greater maximum (1.0-2.3 N · m) and minimum torque (1.0-2.2 N · m). At the same time, the maximum flexion and range of motion of the hip and knee joints were significantly increased (1.8-3.4° and P < 0.05), whereas the ankle joint was not affected. In conclusion, the biomechanical changes due to a longer crank did not alter the metabolic cost of pedalling, although they could have long-term adverse effects. Therefore, in case of doubt between two lengths, the shorter one might be recommended.

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• Differences in pedalling technique between road cyclists of different competitive levels.

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  Differences in pedalling technique between road cyclists of different competitive levels.

  Author(s)

  García-López, Díez-Leal, Ogueta-Alday, Larrazabal, Rodríguez-Marroyo

  Date

  2016-09-01

  Source

  Joural of Sports Sciences

  The purpose of this study was to compare the pedalling technique in road cyclists of different competitive levels. Eleven professional, thirteen elite and fourteen club cyclists were assessed at the beginning of their competition season. Cyclists’ anthropometric characteristics and bike measurements were recorded. Three sets of pedalling (200, 250 and 300 W) on a cycle ergometer that simulated their habitual cycling posture were performed at a constant cadence (~90 rpm), while kinetic and kinematic variables were registered. The results showed no differences on the main anthropometric variables and bike measurements. Professional cyclists obtained higher positive impulse proportion (1.5-3.3% and P < 0.05), mainly due to a lower resistive torque during the upstroke (15.4-28.7% and P < 0.05). They also showed a higher ankle range of movement (ROM, 1.1-4.0° and P < 0.05). Significant correlations (P < 0.05) were found between the cyclists’ body mass and the kinetic variables of pedalling: positive impulse proportion (r = -0.59 to -0.61), minimum (r = -0.59 to -0.63) and maximum torques (r = 0.35-0.47). In conclusion, professional cyclists had better pedalling technique than elite and club cyclists, because they opted for enhancing pulling force at the recovery phase to sustain the same power output. This technique depended on cycling experience and level of expertise.

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• Effect of Growth Hormone (GH) on Glycerol and Free Fatty Acid Metabolism during Exhaustive Exercise in GH-Deficient Adults

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  Effect of Growth Hormone (GH) on Glycerol and Free Fatty Acid Metabolism during Exhaustive Exercise in GH-Deficient Adults

  Author(s)

  J. Gibney, M.L. Healy, M. Stolinski, S.B. Bowes, C. Pentecost, L. Breen, C. McMillan, D.L. Russell-Jones, P.H. Sonksen, A.M. Umpleby

  Date

  2003-04-01

  Source

  The Journal of Clinical Endocrinology & MetabolismApril 1, 2003 vol. 88 no. 4 1792-1797

  GH is an important regulator of fat metabolism at rest, but it is not known whether it regulates fat metabolism during exercise. To determine whether physiologic concentrations of GH influence fat metabolism during exercise, we randomized 16 GH-deficient adults, receiving long-term (mean duration, 5 yr) GH replacement, to either continue GH (n = 8) or receive identical placebo (n = 8) for a 3-month period. Metabolic studies, at rest, during and following exhaustive exercise were carried out at baseline and at the end of the 3 months. The rate of appearance of glycerol (glycerol Ra, an index of lipolysis) and free fatty acids (FFA, FFA Ra) and the rate of disappearance of FFA (FFA Rd) in the plasma were measured using infusions of 2H5-glycerol and 1-13C-palmitic acid. Changes in body composition were assessed using dual-energy x-ray absorptiometry scanning and anthropometric measurements. In the baseline studies, exercise resulted in an increase in plasma glycerol and FFA concentrations, glycerol Ra, FFA Ra, and FFA Rd (P < 0.001). Three months of GH withdrawal resulted in reductions in plasma glycerol and FFA, glycerol Ra, FFA Ra, and FFA Rd at rest (P < 0.05 vs. baseline) and during exercise (P < 0.05 vs. baseline and vs. GH treated). Lean body mass decreased after 3 months of GH withdrawal, but total body fat, trunk fat, waist circumference, and the sum of skinfold thicknesses increased after 3 months of GH withdrawal (P < 0.05 vs. baseline and vs. GH treated). Fasting insulin and homeostasis model assessment of insulin resistance decreased after 3 months of GH withdrawal (P < 0.05 vs.baseline and vs. GH treated). In summary, GH withdrawal for 3 months resulted in reductions in release of glycerol and FFA into the circulation and uptake of FFA into the tissues during intense exercise. These changes were accompanied by reduced lean body mass and increased total body and trunk fat. Further studies are required to determine whether reduced mobilization of fat during exercise contributes to reduced exercise capacity and increased body fat in GH-deficient adults.

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• Effects of toe-in angles on knee biomechanics in cycling of patients with medial knee osteoarthritis

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  Effects of toe-in angles on knee biomechanics in cycling of patients with medial knee osteoarthritis

  Author(s)

  Jacob K. Gardner, Songning Zhang, Hairui Liu, Gary Klipple, Candice Stewart, Clare E. Milner, Irfan M. Asif

  Date

  2015-01-13

  Source

  Clinical Biomechanics 30 (2015) 276–282

  Abstract
  BACKGROUND:
  Cycling is commonly prescribed for knee osteoarthritis, but previous literature on biomechanics during cycling and the effects of acute intervention on osteoarthritis patients does not exist. Due to their altered knee kinematics, osteoarthritis patients may be at greater risk of osteoarthritis progression or other knee injuries during cycling. This study investigated the effects of reduced foot progression (toe-in) angles on knee joint biomechanics in subjects with medial compartment knee osteoarthritis.
  METHODS:
  Thirteen osteoarthritis and 11 healthy subjects participated in this study. A motion analysis system and custom instrumented pedal was used to collect 5 pedal cycles of kinematic and kinetic data in 1 neutral and 2 toe-in conditions (5° and 10°) at 60 RPM and 80W.
  FINDINGS:
  For peak knee adduction angle, there was a 61% (2.7°) and a 73% (3.2°) decrease in the 5° and 10° toe-in conditions compared to neutral in the osteoarthritis group and a 77% (1.7°) and 109% (2.4°) decrease in the healthy group for the 5° and 10° conditions, respectively. This finding was not accompanied by a decrease in pain or peak knee abduction moment. A simple linear regression showed a positive correlation between Kelgren-Lawrence score and both peak knee adduction angle and abduction moment.
  INTERPRETATION:
  For individuals who cycle with increased knee adduction angles, decreasing the foot progression angle may be beneficial for reducing the risk of overuse knee injuries during cycling by resulting in a frontal plane knee alignment closer to a neutral position.
  Copyright © 2015 Elsevier Ltd. All rights reserved.

  KEYWORDS:
  Cycling ergometer; Knee abduction moment; Knee adduction angle; Medial knee OA; Osteoarthritis

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• Exercise Performance Falls over Time in Patients with Chronic Kidney Disease Despite Maintenance of Hemoglobin Concentration

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  Exercise Performance Falls over Time in Patients with Chronic Kidney Disease Despite Maintenance of Hemoglobin Concentration

  Author(s)

  Murray J. Leikis, Michael J. McKenna, Aaron C. Petersen, Annette B. Kent, Kate T. Murphy, James A. Leppik, Xiaofei Gong, Lawrence P. McMahon

  Date

  2006-04-01

  Source

  Clinical Journal of the American Society of Nephrology, CJASN May 2006 vol. 1 no. 3 488-495

  Physical function is limited in patients with kidney disease, although previous studies have been confounded by anemia. What is not clear is how physical performance changes over time as renal function deteriorates. A cohort of 12 patients (10 male, two female; mean +/- SD age 49 +/- 11 yr) who had stages 3 to 4 chronic kidney disease without previous anemia were examined, and nine were followed for a 2-yr period. Assessments were made of peak oxygen consumption (VO2peak) by cycle ergometry, leg extension strength, and fatigue on an isokinetic dynamometer and thigh muscle cross-sectional area (TMCSA) by computed tomography. At baseline, creatinine clearance was 31 +/- 13 ml/min and hemoglobin concentration ([Hb]) was 129 +/- 9 g/L. VO2peak was low (1.88 L/min, 82% of predicted), and maximal isometric voluntary contraction was 188 +/- 42 Nm, with a TMCSA of 144 +/- 27 cm2. VO2peak correlated with creatinine clearance corrected for body surface area (r = 0.613, P = 0.034) but not to [Hb]. VO2peak adjusted for patient weight correlated with leg fatigue (r = -0.693, P = 0.012). For those with follow-up tests, there were falls in renal function by 28% (P = 0.007) and VO2peak by 9% (P = 0.03), whereas [Hb] did not change. Leg strength fell across a range of isokinetic speeds (P = 0.04), whereas no change in TMCSA was observed. In conclusion, exercise performance as measured by aerobic (VO2peak) and leg strength tests were reduced in patients with stages 3 to 4 chronic kidney disease. As renal function declined over time, there was a corresponding decline in exercise performance even when [Hb] was maintained.

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• High Performance Cycling – Chapter 18.

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  High Performance Cycling – Chapter 18.

  Author(s)

  Asker-Jeukendrup, Adrie van Diemen, Jabik Jan Bastiaans

  Date

  2002-01-01

  Source

  Human Kinetics

  Strength and Flexibility.

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• Impaired Mitochondrial Function and Insulin Resistance of Skeletal Muscle in Mitochondrial Diabetes

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  Impaired Mitochondrial Function and Insulin Resistance of Skeletal Muscle in Mitochondrial Diabetes

  Author(s)

  Julia Szendroedi, Albrecht Ingo Schmid, Martin Meyerspeer, Camilla Cervin, Michaela Kacerovsky, Gerhard Smekal, Sabine Gräser-Lang, Leif Groop, Michael Roden

  Date

  2009-11-02

  Source

  Diabetes Care 32:677–679, 2009

  OBJECTIVE— Impaired muscular mitochondrial function is related to common insulin
  resistance in type 2 diabetes. Mitochondrial diseases frequently lead to diabetes, which is mostly attributed to defective ẞ-cell mitochondria and secretion.

  RESEARCH DESIGN AND METHODS— We assessed muscular mitochondrial function and lipid deposition in liver (hepatocellular lipids [HCLs]) and muscle (intramyocellular lipids [IMCLs]) using 31P/1H magnetic resonance spectroscopy and insulin sensitivity and endogenous glucose production (EGP) using hyperinsulinemic-euglycemic clamps combined with isotopic tracer dilution in one female patient suffering from MELAS (myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) syndrome and in six control subjects.

  RESULTS— The MELAS patient showed impaired insulin sensitivity (4.3 vs. 8.6 ± 0.5 mg •
  Kg-1 • min-1) and suppression of EGP (69 vs. 94 ± 1%), and her baseline and insulin-stimulated
  ATP synthesis were reduced (7.3 and 8.9 vs. 10.6 ± 1.0 and 12.8 ± 1.3 μmol • l-1 • min-1)
  compared with those of the control subjects. HCLs and IMCLs were comparable between the
  MELAS patient and control subjects.

  CONCLUSIONS— Impairment of muscle mitochondrial fitness promotes insulin resistance
  and could thereby contribute to the development of diabetes in some patients with the MELAS
  syndrome.

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• Impaired plasma fatty acid oxidation in extremely obese women

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  Impaired plasma fatty acid oxidation in extremely obese women

  Author(s)

  John P. Thyfault, Raymond M. Kraus, Robert C. Hickner, Amy W. Howell, Robert R. Wolfe, G. Lynis Dohm.

  Date

  2004-07-05

  Source

  American Journal of Physiology Endocrinology and Metabolism 287: E1076 –E1081, 2004

  Skeletal muscle from extremely obese individuals exhibits decreased lipid oxidation compared
  with muscle from lean controls. It is unknown whether this effect is observed in vivo or whether the phenotype is preserved after massive weight loss. The objective of this study was to compare free fatty acid (FFA) oxidation during rest and exercise in female subjects who were
  either lean [n = 7; body mass index (BMI) = 22.6 ± 2.2 kg/m2] or extremely obese (n = 10; BMI = 40.8 ± 5.4 kg/m2) or postgastric bypass patients who had lost >45 kg (weight reduced) (n = 6; BMI = 33.7 ± 9.9 kg/m2) with the use of tracer ([13C]palmitate and [14C]acetate) methodology and indirect calorimetry. The lean group oxidized significantly more plasma FFA, as measured by percent fatty acid uptake oxidized, than the extremely obese or weight-reduced group during rest (66.6 ± 14.9 vs. 41.5 ± 16.4 vs. 39.9 ±15.3%) and exercise (86.3 ± 11.9 vs. 56.3 ± 22.1 vs. 57.3 ± 20.3%, respectively). BMI significantly correlated with percent uptake oxidized during both rest (r = -0.455) and exercise (r = -0.459). In conclusion, extremely obese women and weight-reduced women both possess inherent defects in plasma FFA oxidation, which may play a role in massive weight gain and associated comorbidities.

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• Mechanical and electromyographic responses during the 3-min all-out test in competitive cyclists

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  Mechanical and electromyographic responses during the 3-min all-out test in competitive cyclists

  Author(s)

  Andrea Nicolò, Ilenia Bazzucchi, Francesco Felici, Federica Patrizio, Massimo Sacchetti

  Date

  2015-08-24

  Source

  Journal of Electromyography and Kinesiology 25 (2015) 907–913

  This research suggest that muscle fatigue substantially affects performance in the 3-min all-out test, expanding on the traditional bioenergetic explanation that performance is limited by rate and capacity of energy supply.

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• Physiologic responses to two distinct maximal cardiorespiratory exercise protocols

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  Physiologic responses to two distinct maximal cardiorespiratory exercise protocols

  Author(s)

  Rebecca D Larson, Gregory S Cantrell, Carl J Ade, John W Farrell III, David J Lantis, Monica A Barton and Daniel J Larson

  Date

  2015-06-01

  Source

  International Journal of Sports and Exercise Medicine

  Abstract
  Purpose: The purpose of this study was to compare physiologic
  responses elicited by a ramp protocol to those elicited by a staged
  protocol.
  Methods: 57 subjects were recruited and consented to be tested
  on two separate occasions across one week using a magneticallybraked
  cycle ergometer. Expired gases were collected using a
  calibrated metabolic cart. Both protocols began at a workload of
  body weight (in kilograms; BWkgs.) in watts (W) and increased by
  50% of BWkgs every 2 minutes or 1W every 2 seconds, for the
  staged and ramped protocols respectively.
  Results: The staged protocol elicited a greater heart rate max
  (HRmax; p<0.01), minute ventilation (VE; p<0.05), time to
  exhaustion (TTE; p<0.001), blood lactate (La p<0.001), and blood
  lactate at 1-minute post exercise (La-1 p<0.01), whereas the ramp
  protocol elicited a greater peak workload (PWL; p<0.001). Maximal
  oxygen consumption (VO2
  max), gas exchange threshold (GET),
  and respiratory compensation point (RCP) were similar between
  protocols. Bland-Altman plots demonstrated strong agreement and
  minimal biases between protocols.
  Conclusions: The results highlight different responses elicited by
  two distinct maximal cardiorespiratory exercise tests and indicate
  the importance of selecting the correct maximal exercise testing
  protocol; whether quantifying responses to maximal exercise or
  writing an exercise prescription. Interestingly, the ramp protocol
  elicited a similar VO2
  max and a significantly greater peak workload
  in approximately half the time.
  Keywords
  Oxygen consumption, Gas exchange threshold, Respiratory
  compensation point, Ramped exercise, Staged exercise

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• Physiology and training of a world-champion paratriathlete.

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  Physiology and training of a world-champion paratriathlete.

  Author(s)

  Mujika I, Orbañanos J, Salazar H.

  Date

  2015-02-01

  Source

  International journal of sports physiology and performance · February 2015

  Abstract
  Paratriathlon will debut at the Rio 2016 Paralympic Games, but research documenting the physiological attributes and training practices of elite paratriathletes is lacking. This case study reports on the physiology and training of a long-distance worldchampion male paratriathlete (below-the-knee amputee) over 19 mo. His body mass and skinfolds declined respectively by ~4 kg and 30% in 2 mo and remained relatively constant thereafter. His swim test velocity increased by 4.4% over 6 mo but declined back to baseline thereafter. His absolute and relative cycling maximal aerobic power improved progressively by 21.8% and 32.6%, respectively. His power output at the individual lactate threshold (ILT) improved by 39.5% and 51.6%, and his power output at the onset of blood lactate accumulation (OBLA), by 59.7% and 73.4%. His maximal running aerobic velocity improved by 12.8%, and his velocity at ILT and OBLA increased by 38.9% and 44.9%, respectively. Over 84 wk he performed 813 training sessions (248 swim, 229 bike, 216 run, 120 strength), ie, 10 ± 3 sessions/week (mean ± SD). Swim, bike, and run volumes were 709 km (8 ± 3 km/wk), 519 h (6 ± 4 h/wk), and 164 h (2 ± 1 h/wk), respectively. Training at intensities below ILT, between ILT and OBLA, and above OBLA for swim were 82% ± 3%, 14% ± 1%, 4.4% ± 0.4%; for bike, 91% ± 3%, 6.2% ± 0.5%, 3.3% ± 0.3%; and for run, 88% ± 1%, 8.0% ± 0.3%, 3.5% ± 0.1%. The training volume for each discipline was lower than previously reported for competitive able-bodied Olympic-distance triathletes. He won the long-distance world championship in 8 h 14 min 47 s, nearly 30 min faster than his nearest competitor.

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• RELATIONSHIP BETWEEN STRENGTH AND POWER PRODUCTION CAPACITIES IN TRAINED SPRINT TRACK CYCLISTS

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  RELATIONSHIP BETWEEN STRENGTH AND POWER PRODUCTION CAPACITIES IN TRAINED SPRINT TRACK CYCLISTS

  Author(s)

  James Vercoe, Mike R. McGuigan

  Date

  2018-01-01

  Source

  Kinesiology 50(2018) Suppl.1

  The purpose of this study was to investigate the relationship between strength and power capabilities in trained sprint track cyclists. Ten participants including six women and four men (age: 22.1±6.8 years, body height: 176.1±6.7 cm, body weight: 72.1±7.9 kg) performed isometric mid-thigh pull (IMTP) and isokinetic sprint tests. Variables measured included peak force (PF), peak rate of force development (PRFD) for the IMTP and maximal torque and maximal power (Pmax) for the isokinetic sprint test. There was a strong relationship between PF on the IMTP and maximal peak torque values across five isokinetic sprints (r=.890-.925). Strong relationships were also shown between PRFD on the IMTP and maximal torque during isokinetic sprints (r=.696-.755). No significant relationships were found between PF and Pmax produced during isokinetic sprints. The findings suggest that isometric testing can provide useful insights into force capabilities of sprint track cyclists. Strength and conditioning practitioners should improve strength and explosive force capabilities of their athletes if the desired outcome is to increase torque application and power production during maximal sprint cycling.

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• Relative degree of stimulation-evoked glycogen degradation in muscle fibres of different type in rat gastrocnemius.

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  Relative degree of stimulation-evoked glycogen degradation in muscle fibres of different type in rat gastrocnemius.

  Author(s)

  Kernell D, Lind A, van Diemen AB, De Haan A.

  Date

  2012-07-19

  Source

  The Journal of physiology

  1. The relative degree of glycogen degradation, caused in different fibre types by supramaximal electrical activation of the muscle nerve, was investigated in m. gastrocnemius medialis of young adult rats under general pentobarbitone anaesthesia. Four different protocols of intermittent maximal tetanic activation were used, each lasting 6 s (33% duty cycle; fast and slow isovelocity concentric (shortening) contractions, brief- and long-burst isometric contractions; 6 rats per group). All contractions were evoked under ischaemic conditions. 2. Work output finally dropped to 29% of the initial value for the fast concentric and to 87% for the slow concentric contractions. In isometric protocols evoked by the same stimulation patterns, the force x time area rose to 110% for brief-burst contractions and dropped to 95% for the long-burst contractions. 3. Following the physiological procedures, the experimental muscle and its contralateral control were removed and prepared for histochemical analysis. Serial sections were stained for glycogen (periodic acid-Schiff (PAS) method) and myofibrillar ATPase (mATPase), the latter reactions being used for classifying the fibres as types I, IIA, IIBd and IIBm. 4. For deep ‘red’ regions of non-stimulated contralateral control muscles the optical density of PAS staining was ranked between fibre types such that I < IIA < IIBd < IIBm. In superficial ‘white’ regions of the same muscles, no significant difference in PAS staining density was found between IIBd and IIBm fibres (types I and IIA not present). 5. All contractile protocols produced a significant glycogen degradation in IIBm fibres, and the fast concentric activation procedure was associated with a significant decline of PAS staining in all fibre types. For all activation protocols, the relative degree of glycogen degradation within a given region was ranked such that IIBm > IIBd > IIA > I. For IIBm vs. IIBd fibres, the differences in relative degradation were greater and more consistently significant for superficial white regions than in the deeper red muscle portions. 6. The results are discussed in relation to glycogen degradation measurements in studies of motor unit recruitment. Furthermore, the results from red vs. white muscle regions underline that fibres of seemingly the same mATPase type may differ considerably in other properties.

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• Reliability of MAOD measured at 110% and 120% of peak oxygen uptake for cycling

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  Reliability of MAOD measured at 110% and 120% of peak oxygen uptake for cycling

  Author(s)

  CLARE L. WEBER and DONALD A. SCHNEIDER

  Date

  2001-12-17

  Source

  Medicine & Science in Sports & Exercise Vol. 33, No. 6, 2001, pp. 1056–1059

  Purpose: The purpose of this study was to examine the test-retest reliability of maximal accumulated oxygen deficit (MAOD) measured at 110% and 120% of peak oxygen uptake (V˙
  O2) for cycling in seven untrained male and seven untrained female subjects. Methods: After one familiarization trial, all subjects performed two MAOD tests at a power output corresponding to 110% and two tests at 120% of V˙O2 peak in random order. MAOD was calculated for each subject as the difference between O2 demand during exercise and the measured V˙O2. Results: The mean (±SEM) time to exhaustion for the group was not significantly different between trial 1 (226 ± 13 s) and trial 2 (223 ± 14 s) of the 110% test. Likewise, the difference in the time to exhaustion between trial 1 (158 ± 11 s) and trial 2 (159 ± 10 s) was not significant for the 120% test. The intraclass correlation coefficients for the time to exhaustion were 0.95 for the 110% test and 0.98 for the 120% test. The mean MAOD value
  obtained in trial 1 (2.62 ± 0.17 L) was not significantly different from the mean value obtained in trial 2 (2.54 ± 0.19 L) for the 110% test. Additionally, the mean values for the two trials did not differ significantly for MAOD (2.64 ± 0.21 L for trial 1 and 2.63 ± 0.19L for trial 2) in the 120% test. The intraclass correlation coefficients for MAOD were 0.95 for the 110% test and 0.97 for the 120%test. All intraclass correlation coefficients were significant at P < 0.001. Conclusions: When conducted under standardized conditions, the determination of MAOD for cycling was highly repeatable at both 110% and 120% of V˙O2 peak in untrained male and female subjects.

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• Reliability of the Lode Excalibur Sport Ergometer and Applicability to computrainer Electromagnetically Braked Cycling Training Device

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  Reliability of the Lode Excalibur Sport Ergometer and Applicability to computrainer Electromagnetically Braked Cycling Training Device

  Author(s)

  EARNEST, CONRAD P.; WHARTON, RICHARD P.; CHURCH, TIMOTHY S.; LUCIA, ALEJANDRO

  Date

  2005-02-21

  Source

  Journal of Strength and Conditioning Research, 2005, 19(2), 344–348

  New technology allows cyclists to train via power output (PO) in addition to heart rate (HR). For those athletes undertaking seasonal laboratory testing (e.g., V˙O2, lactate threshold),
  it is imperative that athletes be able to directly apply this information to their training device. We examined the reliability of a standardized laboratory ergometer (Lode Excalibur Sport)
  and its applicability to an electromagnetically braked ergometer (Computrainer) in 2 phases. Phase I (n = 12) examined the reliability of the Lode. Phase II (n = 14) compared the Lode to the Computrainer using a randomized, counterbalance assignment.Following warm-up, each trial started at 100 W, progressing 50W every 3 minutes to exhaustion. Outcomes were time-to-exhaustion (TTE), peak PO (W) (POpeak), peak HR (HRpeak), and ventilatory (VT) and respiratory compensation (RCP) thresholds. We used a repeated measures analysis of variance (ANOVA), Tukey post hoc analysis, regression analysis, Bland-Altman plots, and coefficient of variation (CV) analysis for each variable. During phase I, we found no significant difference for any variable, minimal dispersion of V˙O2 during Bland-Altman analysis, and a low CV at each test stage (≤ 5%). During phase II, significant differences and higher CV for most parameters (all data; p < 0.001) were observed for Lode versus Computrainer: TTE
  (21 minutes, 12 seconds ± 3 minutes, 12 seconds vs. 19 minutes, 9 seconds ± 2 minutes, 36 seconds; CV 5 16%), POpeak (335 ± 57.8 W vs. 295 ± 47.1 W, CV 5 17%), as well as PO at VT (CV = 51%) and RCP (CV = 24%; p < 0.01). We conclude that coaches and cyclists may need to use some caution when directly transferring results obtained from laboratory testing to the Computrainer training device.

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• The effects of replacing a portion of endurance training by explosive strength training on performance in trained cyclists.

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  The effects of replacing a portion of endurance training by explosive strength training on performance in trained cyclists.

  Author(s)

  Bastiaans JJ, van Diemen AB, Veneberg T, Jeukendrup AE.

  Date

  2012-07-19

  Source

  European Journal of Applied Physiology

  To investigate the effects of replacing a portion of endurance training by strength training on exercise performance, 14 competitive cyclists were divided into an experimental (E; n = 6) and a control (C; n = 8) group. Both groups received a training program of 9 weeks. The total training volume for both groups was the same [E: 8.8 (1.1) h/week; C: 8.9 (1.7) h/week], but 37% of training for E consisted of explosive-type strength training, whilst C received endurance training only. Simulated time trial performance (TT), short-term performance (STP), maximal workload (Wmax) and gross (GE) and delta efficiency (DE) were measured before, after 4 weeks and at the end of the training program (9 weeks). No significant group-by-training effects for the markers of endurance performance (TT and Wmax) were found after 9 weeks, although after 4 weeks, these markers had only increased (P < 0.05) in E. STP decreased (P < 0.05) in C, whereas no changes were observed in E. For DE, a significant group-by-training interaction (P < 0.05) was found, and for GE the group-by-training interaction was not significant. It is concluded that replacing a portion of endurance training by explosive strength training prevents a decrease in STP without compromising gains in endurance performance of trained cyclists.

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• The most economical cadence increases with increasing workload

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  The most economical cadence increases with increasing workload

  Author(s)

  Oivind Foss, Jostein Hallén

  Date

  2004-08-09

  Source

  European Journal of Applies Physiology. August 2004, Volume 92, Issue 4-5, pp 443-451

  Several studies have suggested that the most economical cadence in cycling increases with increasing workload. However, none of these studies have been able to demonstrate this relationship with experimental data. The purpose of this study was to test the hypothesis that the most economical cadence in elite cyclists increases with increasing workload and to explore the effect of cadence on performance. Six elite road cyclists performed submaximal and maximal tests at four different cadences (60, 80, 100 and 120 rpm) on separate days. Respiratory data was measured at 0, 50, 125, 200, 275 and 350 W during the submaximal test and at the end of the maximal test. The maximal test was carried out as an incremental test, conducted to reveal differences in maximal oxygen uptake and time to exhaustion (short-term performance) between cadences. The results showed that the lowest oxygen uptake, i.e. the best work economy, shifted from 60 rpm at 0 W to 80 rpm at 350 W (P<0.05). No difference was found in maximal oxygen uptake among cadences (P>0.05), while the best performance was attained at the same cadence that elicited the best work economy (80 rpm) at 350 W (P<0.05). This study demonstrated that the most economical cadence increases with increasing workload in elite cyclists. It was further shown that work economy and performance are related during short efforts (~5 min) over a wide range of cadences.

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• The Sweating Foot: Local Differences in Sweat Secretion During Exercise-Induced Hyperthermia

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  The Sweating Foot: Local Differences in Sweat Secretion During Exercise-Induced Hyperthermia

  Author(s)

  Taylor, Nigel A.S.; Caldwell, Joanne N.; Mekjavic, Igor B.

  Date

  2006-10-10

  Source

  Aviation, Space, and Environmental Medicine, Volume 77, Number 10, October 2006 , pp. 1020-1027(8)

  Introduction: Little is known regarding local differences in foot sweat secretion. Since such information is important to our understanding of sweat gland control for thermoregulatory modeling and for the design of footwear we explored this topic. Methods: Local sweat rates were investigated across core temperatures from 37-39°C, achieved using endogenous (cycling) and exogenous heat (water-perfusion garment: 46°C). Six healthy adults (three men, three women) performed one-legged, incremental cycling in a heated, climate-controlled chamber (36°C, 60% relative humidity). Sweat rates were measured at the forehead and stationary (left) foot (capsules 3.16 cm2): three dorsal sites (base of toes, second metatarsal, and mid point), the lateral, and the central plantar surfaces. Results: Terminal core temperatures ranged between 38.3-39.1°C, with peak heart rates of 155-187 bpm. Most foot sweat rates were < 50% of that observed at the forehead: dorsal 1 (38%); dorsal 2 (54%); dorsal 3 (37%); lateral (24%); and plantar surfaces (18%). When averaged across the trial, local sweat rates were: 2.61 (forehead); 0.98 (dorsal 1); 1.39 (dorsal 2); 0.95 (dorsal 3); 0.62 (lateral); and 0.47 mg • cm−2 • min−1 (plantar). Conclusion: Two key observations emerged. First, sweat secretion from the experimental foot averaged 30 ml • h−1, peaking in the last 5 min at 50 ml • h−1. Second, approximately 70% of the measured sweat flow emanated from the upper skin surfaces, with only 30% coming from the plantar surface.

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• Validity of criteria for establishing maximal O2 uptake during ramp exercise tests

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  Validity of criteria for establishing maximal O2 uptake during ramp exercise tests

  Author(s)

  David C. Poole, Baryl P. Wilkerson, Andrew M. Jones

  Date

  2008-03-10

  Source

  European Journal of Applied Physiology, March 2008, Volume 102, Issue 4, pp 403-410

  The incremental or ramp exercise test to the limit of tolerance has become a popular test for determination of maximal O2 uptake (V˙O2max). However, many subjects do not evidence a definitive plateau of the V˙O2 -work rate relationship on this test and secondary criteria based upon respiratory exchange ratio (RER), maximal heart rate (HRmax) or blood [lactate] have been adopted to provide confidence in the measured V˙O2max. We hypothesized that verification of V˙O2max using these variables is fundamentally flawed in that their use could either allow underestimation ofV˙O2max (if, for any reason, a test were ended at a sub-maximal V˙O2 ), or alternatively preclude subjects from recording a valid V˙O2max. Eight healthy male subjects completed a ramp exercise test (at 20 W/min) to the limit of tolerance on an electrically braked cycle ergometer during which pulmonary gas exchange was measured breath-by-breath and blood [lactate] was determined every 90 s. Using the most widely used criterion values of RER (1.10 and 1.15), V˙O2max as determined during the ramp test (4.03 ± 0.10 l/min) could be undermeasured by 27% (2.97 ± 0.24 l/min) and 16% (3.41 ± 0.15 l/min), respectively (both P < 0.05). The criteria of HRmax (age predicted HRmax ± 10 b/min) and blood [lactate] (≥8 mM) were untenable because they resulted in rejection of 3/8 and 6/8 of the subjects, most of whom (5/8) had demonstrated a plateau of V˙O2max atV˙O2max. These findings provide a clear mandate for rejecting these secondary criteria as a means of validating V˙O2max on ramp exercise tests.

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• Within-day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes

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  Within-day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes

  Author(s)

  Monica K. Torstveit, Ida Fahrenholtz, Thomas B. Stenqvist, Øystein Sylta, Anna Melin

  Date

  2018-03-09

  Source

  Human Kinetics Journals

  Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health. We aimed to estimate and compare within-day energy balance (WDEB) in male athletes with suppressed and normal resting metabolic rate (RMR) and explore if within-day energy deficiency (WDED) is associated with endocrine markers of energy deficiency. Thirty-one male cyclists, triathletes, and long-distance runners recruited from regional competitive sports clubs were included. The protocol comprised measurements of RMR by ventilated hood, and energy intake and energy expenditure to predict RMRratio (measured RMR/predicted RMR), energy availability (EA), 24-hour energy balance (EB) and WDEB in 1-hour intervals, assessment of body-composition by dual-energy X-ray absorptiometry, and blood plasma analysis. Subjects were categorized as having suppressed (RMRratio < 0.90, n=20) or normal RMR (RMRratio > 0.90, n=11). Despite no observed differences in 24-hour EB or EA between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8 – 21.8] hours vs. 10.8 [2.5 – 16.4], P=0.023), and had larger single-hour energy deficits compared to subjects with normal RMR (3265 ± 1963 kcal vs. -1340 ± 2439, P=0.023). Larger single-hour energy deficits were associated with higher cortisol levels (r = -0.499, P=0.004) and a lower testosterone:cortisol ratio (r = 0.431, P=0.015), but no associations with T3 or fasting blood glucose were observed. In conclusion, WDED was associated with suppressed RMR and catabolic markers in male endurance athletes.

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