Stephanie G. Harger

The addition of fenugreek extract (Trigonella foenum-graecum) to glucose feeding increases muscle glycogen resynthesis after exercise

Summary.The purpose of this study was to determine the effects of ingesting an oral supplement containing 4-Hydroxyisoleucine (4-OH-Ile, isolated from fenugreek seeds [Trigonella foenum-graecum]) with a glucose beverage on rates of post-exercise muscle glycogen resynthesis in trained male cyclists. Following an overnight fast (12 hr), subjects completed a 90-minute glycogen depletion ride after which a muscle biopsy was obtained from the vastus lateralis. Immediately and 2 hours after the muscle biopsy, subjects ingested either an oral dose of dextrose (Glu) (1.8 g·kg BW−1) or 4-OH-Ile supplement (Glu+4-OH-Ile, including 2.0 mg·kg−1 4-OH-Ile with the same oral dose of dextrose) with a second muscle biopsy 4 hours after exercise. Post exercise muscle glycogen concentration was similar for both trials. Overall, there was a significant increase in glucose and insulin concentrations from time 0 throughout the majority of the 4-hour recovery period, with no significant differences between the two trials at any time point. Although muscle glycogen concentration significantly increased from immediately post exercise to 4 hr of recovery for both trials, the net rate of muscle glycogen resynthesis was 63% greater during Glu+4-OH-Ile (10.6±3.3 vs. 6.5±2.6 g·kg wet wt.−1·hr.−1 for the Glu+4-OH-Ile and Glu trials, respectively). These data demonstrate that when the fenugreek extract supplement (4-OH-Ile) is added to a high oral dose of dextrose, rates of post-exercise glycogen resynthesis are enhanced above dextrose alone.

Effects of an Electrolyte Additive on Hydration and Drinking Behavior During Wildfire Suppression

Abstract Objective.—The purpose of this study was to compare the effects of a water + electrolyte solution versus plain water on changes in drinking behaviors, hydration status, and body temperatures during wildfire suppression. Methods.—Eight participants consumed plain water, and eight participants consumed water plus an electrolyte additive during 15 hours of wildfire suppression. Participants wore a specially outfitted backpack hydration system equipped with a digital flow meter system affixed inline to measure drinking characteristics (drinking frequency and volume). Body weight and urine-specific gravity were collected pre- and postshift. Ambient, core, and skin temperatures were measured continuously using a wireless system. Work output was monitored using accelerometry. Results.—There were no differences between groups for body weight, drinking frequency, temperature data, activity, or urine-specific gravity (1.019 ± 0.007 to 1.023 ± 0.010 vs. 1.019 ± 0.005 to 1.024 ± 0.009 for water and water + electrolyte groups pre- and postshift, respectively; P < .05). There was a main effect for time for body weight, demonstrating an overall decrease (78.1 ± 13.3 and 77.3 ± 13.3 kg pre- and postshift, respectively; P < .05) across the work shift. The water group consumed more total fluid (main effect for treatment) than the water + electrolyte group (504 ± 472 vs. 285 ± 279 mL·h−1 for the water and water + electrolyte groups, respectively; P < .05). Conclusion.—The addition of an electrolyte mixture to plain water decreased the overall fluid consumption of the water + electrolyte group by 220 mL·h−1 (3.3 L·d−1). Supplementing water with electrolytes can reduce the amount of fluid necessary to consume and transport during extended activity. This can minimize carrying excessive weight, possibly reducing fatigue during extended exercise.

Glycogen resynthesis and exercise performance with the addition of fenugreek extract (4-hydroxyisoleucine) to post-exercise carbohydrate feeding

Summary.The purpose of this study was to determine the effect of adding fenugreek extract (FG) to post-exercise carbohydrate feeding on glycogen resynthesis and subsequent exercise performance in normoglycemic male endurance athletes. A muscle biopsy sample was obtained from the vastus lateralis from subjects prior to exercise for 5 h at 50% of peak cycling power (52.1 ± 3.3% of VO2 peak). A second muscle biopsy sample was obtained immediately after exercise. Immediately after and 2 h after the second biopsy subjects ingested either an oral dose of dextrose (GLU) (1.8 g · kg BW−1) or GLU with FG containing 1.99 ± 0.20 mg · kg−1 4-hydroxyisoleucine (GLU + FG) in a randomized, cross-over, double blind design. At 4 h post-exercise a third biopsy was taken and subjects received a standardised meal along with FG or a placebo capsule. At 15 h post-exercise subjects underwent their final muscle biopsy before completing a simulated 40 km cycling time trial. There was no difference in muscle glycogen at any time between GLU and GLU + FG. Additionally, 40 km time trial performance was similar for average power output (221 ± 28 vs. 213 ± 16 watts) and for time to completion (69.7 ± 3.7 vs. 70.5 ± 2.2 min) for the GLU and GLU + FG, respectively. Despite earlier data to the contrary, the present results do not support an effect of fenugreek supplementation on glycogen resynthesis, even though this may have been the result of differences in experimental protocol.

Liquid and Solid Carbohydrate Feedings Increase Self-Selected Work Rates During Arduous Wildfire Suppression

Our laboratory has demonstrated that the total energy expenditure of extended wildfire suppression may exceed 26 MJ.d (MSSE 34(6):1048-54, 2002). Moreover, the majority of the total daily energy intake is provided before and after the extended workshift and supplemented with a mid-day sack lunch. PURPOSE: To determine the effects of supplemental carbohydrate (CHO) feedings on self-selected work rates during extended arduous wildfire suppression. METHODS: Subjects included wildland firefighters (N=20 Hotshots) during two wildfires in ID and OR. Subjects consumed a CHO (200 ml.hr, 20% maltodextrin (40g.hr)) or placebo (PLA) drink in a counter-balanced crossover design and were allowed ad lib water intake during the day. Blood samples were collected at two-hour intervals with automated glucometers. Self-selected hourly work rate was determined using CSA accelerometer count data. Data were analyzed using a priori planned comparisons across trials. RESULTS: During the 20% CHO trials, blood glucose (mM) was significantly higher (p<0.05) immediately prior to lunch (CHO=5.9±1, PLA=5.4±0.9) and at four (CHO=6.7±1.1, PLA =5.6±.8) and six hours (CHO=6.2±1.0, PLA=5.0±0.6) post lunch, and immediately post shift (CHO=5.8±1.3, PLA=4.7±0.6). Self-selected work rate was similar across trails during the initial hours post breakfast but were significantly different later in the morning (mean 4-6 hour post breakfast: CHO=58,088±15,730, PLA=40,191±20,070 counts.hr). Work rate was also similar across trials during the early hours after lunch but was significantly different later in the afternoon (mean 4-6 hour post lunch: CHO=64,172±30,501, PLA=47,528±26,541 counts.hr). CONCLUSIONS: Self-selected work rate is higher during arduous wildfire suppression when CHO is delivered at a rate of 40 g.hr (200 ml.hr, 20% solution). Supported by the U.S. Forest Service – Missoula Technology and Development Center.