Hartmanjama8327

Despite differences in economy, cyclists climb in seated and standing positions. Prompted by gaps in research, we compared VO2 and heart rate (HR) (Study 1), muscle activation (Study 2) and breathing and pedaling entrainment (Study 3).

Subjects rode their bicycles on a treadmill in seated and standing positions. In Study 1, VO

and HR of four male cyclists (21.3 ± 1.7 yrs; 69.1 ± 6 ml/kg/min) were collected, alternating positions every 5 minutes for 20 minutes (8 mph, 8% grade). In Study 2, muscle activations of eight male cyclists (24 ± 5 yrs, 67.6 ± 5.5 ml/kg/min) were collected on Rectus Femoris (RF), Biceps Femoris, Vastus Medialis (VM) and Gastrocnemius alternating positions every minute (8 mph, 8% grade). In Study 3, flow rate and entrainment of nine male cyclists (28 ± 7 yrs, 62.7 ± 7.7 ml/kg/min) were collected in 2-minute stages at 6, 8 and 10 mph, (8% grade) alternating positions every minute.

VO

and HR increased standing (3.17± 0.43 L/min, 175 ± 4 bpm) compared to seated (3.06 ± 0.37 L/min, 166 ± 5 bpm) (

< 0.05). Normalized EMG for RF and VM increased standing (47 ± 5%, 57 ± 15%) compared to seated (34 ± 3%, 36 ± 8%) (

< 0.05). Peak Inspiratory and Expiratory Flow increased standing (3.44±0.07 and 2.45±0.05 L/sec) compared to seated (3.09 ±0.06 and 2.21±0.04 L/sec) (

< 0.05).

Uphill cycling while standing results in decreased cycling economy due to physiological and biomechanical variations compared to riding seated.

Uphill cycling while standing results in decreased cycling economy due to physiological and biomechanical variations compared to riding seated.This study aimed to investigate the effects of walking in a hot and humid environment while wearing a combat suit with a load on physiological responses among the Malaysian Military Reserve Officer Training Unit (ROTU) female cadets. Eight healthy female ROTU cadets (age 21.3 ± 1.0 years old; height 156.3 ± 4.9 cm; weight 55.6 ± 7.5 kg) participated in this randomised, crossover trial. They walked for 1 h on a treadmill at 3 km.h-1 while carrying either 8.2 kg load (WL) or without load (WOL) in a room maintained at 30°C and 70% relative humidity. Semaxanib Heart rate, rate of perceived exertion (RPE), and tympanic temperature were recorded at regular intervals during the trials. Nude body weight was recorded before and after the walk to determine body weight loss and sweat rate. Urine samples were also collected before and after the walk to determine urine specific gravity of the participants. There was a significant main effect of time and interaction for heart rate (p less then 0.001) during the experimental trials. Tympanic temperature was significantly higher at 60th min in WL trial (p less then 0.05) compared to the WOL trial. Similarly, RPE was found to be significantly higher in WL trial (p less then 0.01) compared to the WOL trial. However, the percentage of body weight loss and sweat rate was significantly different between trials (p less then 0.05). Wearing a combat suit with a load showed significantly increased metabolic demands compared to wearing combat suit alone during prolonged walking in a hot and humid environment.Cardiorespiratory endurance is an important element of aerobic fitness, particularly in weight management and reducing risk for cardiovascular disease. While there are numerous options for aerobic exercise, rope jumping is often overlooked. In addition to regular exercise and a healthy diet, the American Heart Association strongly recommends rope jumping. The first purpose of this study was to determine the steady state metabolic cost of repetitive jumping on the Digi-Jump machine to evaluate whether exercise on this device is more or less strenuous than similar exercise with a jump rope, as demonstrated in previous literature. A second purpose was to determine the relative intensity of exercise on the Digi-Jump by comparing to VO2max as measured on a treadmill. Twenty-seven participants completed two trials, one jumping trial at a rate of 120 jumps per minute with the jumping height set at 0.5 inch for 5-min on the Digi-Jump, and one graded exercise test using the Bruce protocol. Oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) were measured each minute during each trial. Results of this study indicated that steady state VO2 during the 5-min jump test was reached at the 3rd min. Steady state variables during the jumping trial expressed as percentage of max were as follows VO2 was 57.1% of VO2max; HR was 80.9% of HRmax; RER was 86%of RERmax; and RPE was 75.2% of RPEmax. These data indicate that repetitive jumping is a strenuous activity and similar in intensity to jumping rope, even if the trial is done on the Digi-Jump machine with free-swinging arms and without a jump rope.Currently, no gold standard electromyography (EMG) normalizing technique exists when conducting between-muscle comparisons of muscle activity during isotonic resistance training exercises. The aim of this study was to assess if between-muscle activation during the back-squat differed among electromyography (EMG) normalization techniques when normalizing to (1) 1 repetition maximum (1RM), (2) maximal voluntary isometric contraction (MVIC), and (3) the first of a set of three repetitions (Rep1%) in trained female lifters. Thirteen participants completed a back-squat 1RM, MVIC of the rectus-femoris (RF) and gluteus-maximus (GM), and three repetitions of the back-squat at 80% 1RM. For the 1RM and MVIC normalization techniques, the average of the peak RMS signal of both muscles during the three submaximal reps were normalized to the peak 1RM and MVIC signals. The Rep1% averaged the peak RMS signals of both muscles during the 2nd and 3rd submaximal repetitions normalized to the peak signal during the 1st repetition. The RF-GM between-muscle EMG (ΔEMG) differed among normalization techniques (p less then 0.001, ηp2 = 0.48). Post-hoc pairwise comparisons indicated MVIC normalization elicited different ΔEMG with large effects compared to both 1RM (p = 0.037; d = 1.2) and Rep1% (p = 0.004; d = 1.9) techniques, but the 1RM and Rep1% did not produce different ΔEMG (p = 0.27; d = 0.8). Our findings suggest EMG normalization technique influences the magnitude and direction of between-muscle activation during common lifting exercises, and we recommend normalizing isotonic movements to dynamic normalization methods such as a 1RM or Rep1%.