The effects of specificity of training on rating of perceived exertion at the lactate threshold

To determine the effects of cycle and run training on rating of perceived exertion at the lactate threshold (LT), college men completed a 40-session training program in 10 weeks (n = 6 run training, n = 5 cycle training, n = 5 controls). Pre- and post-training variables were measured during graded exercise tests on both the bicycle ergometer and treadmill. ANOVA on the pre- and post-training difference scores resulted in similar improvements in VO2max for both testing protocols, regardless of training mode. The run training group increased VO2 at the LT by 58.5% on the treadmill protocol and by 20.3% on the cycle ergometer. Cycle trainers increased VO2 LT only during cycle ergometry (+38.7%). No changes were observed in the control group. No differences for RPE at the LT were found before or after training, or between testing protocols for any group. Perception of exercise intensity at the LT ranged from "very light" to "light". The relationship between RPE and %VO2max was altered by the specific mode of training, with trained subjects having a lower RPE at a given %VO2max (no change in RPE at max.). It was concluded that RPE at the LT was not affected by training, despite the fact that after training the LT occurs at a higher work rate and was associated with higher absolute and relative metabolic and cardiorespiratory demands.     

Regulating explosive resistance training intensity using the rating of perceived exertion

Explosive resistance training (ERT) improves older adults' strength and power, and methods to make this form of training more accessible and useful to older adults are needed. The purpose of this study was to evaluate whether the rating of perceived exertion (RPE) scale would predict a broad range of ERT intensities on the leg press with older adults. If successful, then a load-RPE relationship could be used to regulate the intensity of training loads for ERT with older adults, allowing the elimination of maximal strength testing. Twenty-one older adults (≥65 years) with resistance training experience took part in 2 testing sessions. Session 1: Subjects performed high-velocity repetitions on the leg press for up to 9 loads (from 60 to 140% body weight) presented in quasi-randomized order, and then reported their RPE for each load. Session 2: A 1 repetition maximum (1RM) strength test was conducted. Regression analysis revealed that the average RPE across subjects for each load strongly predicted the average %1RM across subjects (R2 = 99.5%; p < 0.001). This allows the establishment of a load-RPE relationship for use in selecting ERT loads for older adults on the leg press. For example, high-intensity loads (70-90% 1RM) that would elicit both strength and power gains when used with ERT aligned with an RPE of 14-16. Lighter loads that may be useful for training for power, but not strength (<70% 1RM), were identified with RPE scores of 13 and lower. The load-RPE relationship may simplify the regulation of intensity of ERT with older adults on the leg press, where the exercising older adult could be guided to select loads according to their RPE.     

Effect of training on the rating of perceived exertion at the ventilatory threshold

The purpose of this study was to determine the effect of training on the rating of perceived exertion (RPE) at the ventilatory threshold. College students were assigned to either training (n = 17) or control (n = 10) groups. Trainers completed 18 interval training sessions (five X 5 min cycling at 90-100% VO2max) and 8 continuous training sessions (40 min running or cycling) in 6 weeks. Pre- and post-training, cardiorespiratory, metabolic, and perceptual variables were measured at the ventilatory threshold during graded exercise tests on a cycle ergometer. Ventilatory threshold was that point above which VE X VO2-1 increased abruptly relative to work rate. Post-training means of trained and control subjects were compared using analysis of covariance, with pre-training values as covariates. Following training, the adjusted means for the trained subjects were significantly greater (p less than 0.05) than for controls for VO2max (6%), and for work rate (20%), VO2 (23%), and %VO2max (13%) at the ventilatory threshold. However, adjusted means for RPE at the ventilatory threshold were not significantly different (2%). Both before and after training, exercise at the ventilatory threshold was perceived as 'somewhat hard' to 'hard' (RPE = 13-15) by both groups. The relationship between RPE and %VO2max was altered by training, with trained subjects having a lower RPE at a given %VO2max. It is concluded that RPE at the ventilatory threshold is not affected by training, despite that after training the ventilatory threshold occurs at a higher work rate and is associated with higher absolute and relative metabolic and cardiorespiratory demands.     

Quantitation of resistance training using the session rating of perceived exertion method

The purpose of this study was to apply the session rating of perceived exertion (RPE) method, which is known to work with aerobic training, to resistance training. Ten men (26.1 +/- 10.2 years) and 10 women (22.2 +/- 1.8 years), habituated to both aerobic and resistance training, performed 3 x 30 minutes aerobic training bouts on the cycle ergometer at intensities of 56%, 71%, and 83% Vo(2) peak and then rated the global intensity using the session RPE technique (e.g., 0-10) 30 minutes after the end of the session. They also performed 3 x 30 minutes resistance exercise bouts with 2 sets of 6 exercises at 50% (15 repetitions), 70% (10 repetitions), and 90% (4 repetitions) of 1 repetition maximum (1RM). After each set the exercisers rated the intensity of that exercise using the RPE scale. Thirty minutes after the end of the bout they rated the intensity of the whole session and of only the lifting components of the session, using the session RPE method. The rated intensity of exercise increased with the %Vo(2) peak and the %1RM. There was a general correspondence between the relative intensity (%Vo(2) peak and % 1RM) and the session RPE. Between different types of resistance exercise at the same relative intensity, the average RPE after each lift varied widely. The resistance training session RPE increased as the intensity increased despite a decrease in the total work performed (p < 0.05). Mean RPE and session RPE-lifting only also grew with increased intensity (p < 0.05). In many cases, the mean RPE, session RPE, and session RPE- lifting only measurements were different at given exercise intensities (p < 0.05). The session RPE appears to be a viable method for quantitating the intensity of resistance training, generally comparable to aerobic training. However, the session RPE may meaningfully underestimate the average intensity rated immediately after each set.     

Effect of alcohol on perceived exertion in relation to heart rate and blood lactate

The purpose of the study was to determine whether the perception of exertion is affected by alcohol during physical performance and whether altered self-rating of exertion is the result of an altered perception per se or of an altered physical capacity to perform work. Ten healthy men participated. Each subject was his own control and received an alcohol dose corresponding to 1 g.kg-1 body mass in 40% solution in the experimental session. The exercise test was performed on a cycle ergometer with an initial intensity of 50 W which was increased stepwise by 50 W at 4-min intervals up to near-maximal. The rating of perceived exertion (RPE) did not differ between alcohol and control sessions. Alcohol induced a significant increase in heart rate during exercise at 50 W (delta x = 8 beats.min-1) and at 100 W (delta x = 10 beats.min-1), while the change at higher intensities was insignificant. The systolic blood pressure and the blood lactate concentration were not significantly changed by alcohol. It is concluded that a moderate dose of alcohol does not alter RPE during physical exercise either per se or secondarily to an altered physical capacity to perform work.     

Effect of Ramadan fasting on feelings,dietary intake,rating of perceived exertion and repeated high intensity short-term maximal performance

The present study was designed to investigate the effect of Ramadan fasting on feelings, dietary intake, rating of perceived exertion (RPE) and repeated high-intensity short-term maximal performance. Thirteen physically active men (age: 21.2 ± 2.9 years, height: 175.6 ± 5.6 cm, body-mass: 72.4 ± 8.6 kg) performed a 5-m shuttle run test (6 × 30-s + 35-s of recovery in-between) during five experimental periods: fifteen days before Ramadan (BR), the first ten days of Ramadan (FR), the last ten days of Ramadan (ER), ten days after Ramadan (AR10) and 20 days after Ramadan (AR20). The study was carried out in Tunisia during the 2016 Ramadan month. During the 5-m shuttle run test, higher distance (HD), total distance (TD) and fatigue index (FI) were recorded. RPE was determined after a 5-min warm-up and after each repetition of the 5-m shuttle run test (the mean RPE score during the test was calculated). Moreover, a feelings scale (FS) was used after the warm-up and after the end of the 5-m shuttle run test. During the five experimental periods, dietary intake was assessed. The results showed that HD, TD and FI during the 5-m shuttle run test were not affected by Ramadan observance (p > 0.05). Likewise, FS scores recorded after the warm-up and the 5-m shuttle run test were not affected by Ramadan fasting (p > 0.05). However, mean RPE scores during the 5-m shuttle run test were significantly lower at ER (4.06 UA), AR10 (3.86 UA) and AR20 (3.71 UA) in comparison to BR (4.51 UA) (p < 0.05). The results showed also that Ramadan fasting has no adverse effect on energy intake, protein (g and %), fat (g and %) and carbohydrate (g). However, the fractional contribution of carbohydrate was significantly higher AR10 than FR (53.1% vs. 45.8%) and ER (53.1% vs. 46.5%) and AR20 than FR (5.92% vs. 45.8%) (p < 0.05). In conclusion, Ramadan fasting has no adverse effect on feelings, dietary intake, and short-term maximal performance. However, the RPE during repeated high intensity short-term maximal exercise was reduced AR20 in comparison to ER.

Abbreviations:

AR: After Ramadan; AR10: Ten days after Ramadan; AR20: Twenty days after Ramadan; BR: Fifteen days before Ramadan; ER: Last ten days of Ramadan; FI: Fatigue index; FR: First ten days of Ramadan; FS: Feelings scale; HD: Higher distance; PSQI: The Pittsburgh Sleep Quality Index; RPE: Rating of Perceived Exertion Scale; TD: Total distance     

The increase of perceived exertion, aches and pain in the legs, heart rate and blood lactate during exercise on a bicycle ergometer

This study was designed to show the general increase in perceived exertion, perception of aches or pain in the legs, heart rate (HR), and blood lactate, and the covariance between these variables during bicycle ergometer work, and to describe individual differences both within and between power levels by testing a large group (28 male students). Estimates of perceived exertion and feelings of aches or pain in the legs were recorded using Borg's category-ratio scale (CR-10). The subjects were tested with a stepwise increase of power levels with 40 W increments up to a voluntary maximum. Though HR increases fairly linearly with power, the other variables follow positively accelerating functions with exponents of about 1.6-2 for the perceptual variables, and an exponent of about 3 for blood lactate. The results from the 8 most fit subjects could be described in the same way as for the whole group except for blood lactate, where there was a need to include a threshold value (b), that, together with a rest value (a), shows the starting point of the function (R = a + c(W - Wo)n). The data support the idea that a combination of heart rate and blood lactate is a better predictor of perceived exertion and feelings of aches and pain in the legs, than is each of the single physiological variables taken alone.     

Contribution of blood lactate to the energy expenditure of weight training

Bioenergetic interpretations of energy transfer specify that rapid anaerobic, substrate-level adenosine triphosphate (ATP) turnover with lactate production is not appropriately represented by an oxygen uptake measurement. Two types of weight training, 60% of 1 repetition maximum (1RM) with repetitions to exhaustion and 80% of 1RM with limited repetitions, were compared to determine if blood lactate measurements, as an estimate of rapid substrate-level ATP turnover, provide a significant contribution to the interpretation of total energy expenditure as compared with oxygen uptake methods alone. The measurement of total energy expenditure consisted of blood lactate, exercise oxygen uptake, and a modified excess postexercise oxygen consumption (EPOC); oxygen uptake-only measurements consisted of exercise oxygen uptake and EPOC. When data from male and female subjects were pooled, total energy expenditure was significantly higher for reps to exhaustion (arm curl, +27 kJ; bench press, +27 kJ; leg press, +38 kJ; p < 0.03) and limited reps (arm curl, +12 kJ; bench press, +23 kJ; leg press, + 24 kJ; p < 0.05) when a separate measure of blood lactate was part of the interpretation. When the data from men and women were analyzed separately, blood lactate often made a significant contribution to total energy expenditure for reps to exhaustion (endurance-type training), but this trend was not always statistically evident for the limited reps (strength-type training) protocol. It is suggested that the estimation of total energy expenditure for weight training is improved with the inclusion, rather than the omission, of an estimate of rapid anaerobic substrate-level ATP turnover.     

Program design based on a mathematical model using rating of perceived exertion for an elite Japanese sprinter: a case study

We investigated the effects of program design on 400-m sprint time by applying a Rating of Perceived Exertion (RPE) mathematical model to training performance. The subject was 24 years old and had been training for 9 years. His best performance in 400-m sprint competitions was 45.50 seconds. Body weight, resting heart rate, training time and RPE were monitored daily after training sessions. Similarly, performance in 400-m races was recorded 9 times during 2003. At the World Championships in Athletics in France, the subject's team placed eighth in the 1,600-m relay. The RPE mathematical model was able to predict changes in performance. Rate of matching was statistically significant (r(2) = 0.83, F ratio = 34.27, p < 0.001). Application of the RPE mathematical model to the design of a training program specific to the needs of a 400-m sprinter indicates a potentially powerful tool that can be applied to accurately assess the effects of training on athletic performance.     

The influence of diet on the growth of Stenonema vicarium (Walker) (Ephemeroptera: Heptageniidae)

Laboratory studies compared the growth rate of Stenonema vicarium (Walker) nymphs on diets of detritus and natural stream periphyton. In three consecutive runs of the experiment, growth rates were consistently higher on periphyton (mean growth rate = 2.1% wet wt. d⁻¹) than detritus (mean = 1.8% wet wt. d⁻¹). The starting date of each run also significantly influenced growth rates. In each treatment growth rates generally decreased over the course of the 3 runs, and ca. one-half of the nymphs in the last run did not molt or grow. It appeared that growth of S. vicarium may be partially controlled by seasonal factors.     

The influence of a respiratory acidosis on the exercise blood lactate response

The purpose of the present study was to examine the influence of a respiratory acidosis on the blood lactate (La) threshold and specific blood La concentrations measured during a progressive incremental exercise test. Seven males performed three step-incremental exercise tests (20 W.min-1) breathing the following gas mixtures; 21% O2 balance-nitrogen, and 21% O2, 4% CO2 balance-nitrogen or balance-helium. The log-log transformation of La oxygen consumption (VO2) relationship and a 1 mmol.l-1 increase above resting values were used to determine a La threshold. Also, the VO2 corresponding to a La value of 2 (La2) and 4 (La4) mmol.l-1 was determined. Breathing the hypercapnic gas mixtures significantly increased the resting partial pressure of carbon dioxide (PCO2) from 5.6 kPa (42 mm Hg) to 6.1 kPa (46 mm Hg) and decreased pH from 7.395 to 7.366. During the incremental exercise test, PCO2 increased significantly to 7.2 kPa (54 mm Hg) and 6.8 kPa (51 mm Hg) for the hypercapnic gas mixtures with nitrogen and helium, respectively, and pH decreased to 7.194 and 7.208. In contrast, blood PCO2 decreased to 4.9 kPa (37 mm Hg) at the end of the normocapnic exercise test and pH decreased to 7.291. A blood La threshold determined from a log-log transformation [1.20 (0.28) l.min-1] or as an increase of 1 mmol.l-1 [1.84 (0.46) l.min-1] was unaffected by the acid-base alterations. Similarly, the VO2 corresponding to La2 and La4 was not affected by breathing the hypercapnic gas mixtures [2.12 (0.46) l.min-1 and 2.81 (0.52) l.min-1, respectively].(ABSTRACT TRUNCATED AT 250 WORDS)     

Goldfish can recover after short-term exposure to 2,4-dichlorophenoxyacetate: Use of blood parameters as vital biomarkers

This study investigated the effects of 2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide, on the metabolism of goldfish, Carassius auratus, using only vital (non-lethal) approaches. After 96 h exposure to 1, 10 or 100 mg/L of 2,4-D selected hematological (total hemoglobin and hematocrit) and biochemical (glucose content, aspartate transaminase and acetylcholinesterase activities) parameters were unchanged in blood of exposed fish. At 100 mg/L of 2,4-D lymphocyte numbers decreased by 8%, whereas promyelocyte and metamyelocyte numbers increased by 7- and 2-fold, respectively. Exposure to 100 mg/L of 2,4-D also elevated carbonyl protein levels (by 2-fold), triglyceride content (by 43%) and alanine transaminase activity (by 46%) in goldfish plasma. All of these hematological and biochemical parameters reverted to control values after a 96 h recovery period. These data indicate that 2,4-D has toxicological effects on goldfish that can be monitored with multiple diagnostic tests using non-lethal blood testing.     

Effects of the number of players and game type constraints on heart rate, rating of perceived exertion, and technical actions of small-sided soccer games

The purpose of this study was to identify the variation of heart rate (HR), rating of perceived exertion (RPE), and technical actions between 2 soccer small-sided games (SSGs; 3 × 3 and 4 × 4) in 3 game type constraints (when playing only offense [OFF], playing only defense [DEF], and both situations [GAME]). Sixteen high-level young male players were analyzed (age 15.75 ± 0.45 years; height 172.4 ± 4.83 cm; body mass 64.5 ± 6.44 kg; HRmax199.1 ± 9.08 b·min(-1); and 8.06 ± 1.98 years of soccer practice). All tasks were performed in 4 periods of 4 minutes interspersed with 2 minutes of active recovery. The HR was measured continuously and then analyzed by the time spent into 4 training zones according to individual %HRmax (zone 1 <75%; zone 2 75-84.9%; zone 3 85-89.9%; and zone 4 ≥90%). Results identified that players were most frequently in zones 2 and 3. The 3 × 3 SSGs elicited higher HR and RPE and the most intense situation was GAME. Despite the known higher frequencies from technical actions in SSGs with fewer players, player effectiveness in 3 × 3 and 4 × 4 was identical. The use of GAME, OFF, and DEF game type constraints should be carefully planned. Using the 3 × 3 format seems more adequate when aiming for aerobic performance optimal effects; however, DEF situations should only be used to promote aerobic recovery effects. The inclusion of an additional player in SSGs had different interactions in game type constraints, and only GAME presented adequate intensity.     

The effect of diet on longevity,fecundity, and the sex ratio of Clitostethus arcuatus (Rossi) (Coleoptera: Coccinellidae)

Clitostethus arcuatus is a major, cosmopolitan predator of some Aleyrodidae. Field collected adult beetles were reared in the laboratory on different diets: Siphoninus phillyreae eggs, Trialeurodes vaporariorum eggs, Sitotroga cerealella eggs, or an artificial diet consisting of honey, yeast, and pollen. All experiments were conducted at 25 ± 2 °C, 65 ± 5% RH and a photoperiod of 16:8 (L:D) h. Female and male C. arcuatus consumed a mean (± SE) of 61 ± 0.6 and 27 ± 0.9 T. vaporariorum eggs d^? 1, respectively, and a mean of 56 ± 2.2 and 29 ± 1.1 S. phillyreae eggs d^? 1, respectively. Significant differences were noted between sexes and between hosts consumed by female C. arcuatus. No feeding occurred on S. cerealella eggs. Although there was a significant difference between rates of oviposition due to diet, fertility rates on different diets did not show significant differences. The sex ratio of C. arcuatus (female:male) was 51.4:48.6, 55.2:44.8, and 54.6:45:4 when adults fed on T. vaporariorum, S. phillyreae, and artificial diet, respectively. These differences were not significantly different. Average longevity (± SE) was 66.4 ± 2.6, 54.9 ± 2.5; 77.3 ± 6.9, 67.5 ± 7.2; and 86.4 ± 4.5 70.3 ± 3.6 days for female and male C. arctuatus, respectively, on T. vaporariorum, S. phillyreae and artificial diet, respectively, with significant differences between sexes and diets. Although developmental duration on T. vaporariorum was longer than ash whitefly, this difference was not significant (mean 27.68 ± 0.31 and 25.09 ± 0.21 days for predators reared on T. vaporariorum and S. phillyreae, respectively). Given its longevity and fecundity on T. vaporariorum, C. arcuatus may be a good choice for mass release on glasshouse crops infected by greenhouse whitefly.     

Effect of natural and laboratory diet on O : N ratio in juvenile lobsters (Homarus americanus)

Oxygen consumption and ammonia excretion rates of juvenile lobsters spanning the size range from shelter-restricted to vagile (7-60 mm CL, carapace length) were measured. There are no significant size-dependent break points in the slope of oxygen consumption or nitrogen excretion rates versus weight in freshly caught wild or laboratory fed lobsters. This suggests that there are no inherent changes in energy metabolism in juvenile lobster in the 7-60 mm CL range (stage V to adolescent lobsters), despite major behavioral shifts related to foraging and shelter use. In addition, the O : N ratio of freshly caught wild lobsters (15.7+/-7.4, mean+/-S.D.) is not significantly different from that of lobsters fed brown algae (13.4+/-4.9) or a mixed carbohydrate/protein diet (13.7+/-6.8) in lab. The O : N ratio of wild lobsters is significantly higher than lobsters fed a high protein diet (7.5+/-2.5) in the lab. This suggests that carbohydrates, particularly algal-derived carbohydrates, make up a significant portion of the metabolic fuel of wild juvenile lobsters from settlement through adolescence.     

Male diet and age influence to inhibit female remating in Ceratitis capitata (Diptera: Tephritidae)

This study evaluated the influence of age and adult nutritional status of Ceratitis capitata males on their ability to inhibit female remating. Their roles and that of copula duration on the amount of sperm transferred to female spermathecae were also analysed. After emergence, adults were kept in separate groups according to their diets (either high protein – 6.5 g of brewer’s yeast, or low protein – 3.5 g of brewer’s yeast) and their age at the time of use in experiments (4, 8, 12, 16 and 20 days old). The results demonstrated that: (i) male age was not a factor that influenced remating when females mated with well‐nourished males; however, the youngest males (4 days old) in the low‐protein group were less efficient in preventing female remating; (ii) 12‐ and 16‐day‐old males fed on a high‐protein diet transferred and produced more sperm than males of other groups; (iii) there was no correlation between copula duration and the amount of sperm transferred to the female; the longest copula durations were observed among low‐protein‐diet/20‐day‐old males. These results suggest that age and nutrition influence the ability of the males to inhibit female remating. The sterile insect technique is most effective when females do not remate after coupling with sterile males, and therefore, the capacity to inhibit female remating is an important characteristic of males released in the field.