Effects of co-ingestion of AAKG and HMB on jumping performance 1 in young track and field athletes

10 Background: The aim of the study was to determine the effect of simultaneous 11 supplementation of β-hydroxy-β-methylbutyrate and L-arginine α-ketoglutarate on lower limb 12 power and muscle damage in medium distance runners aged 15.3 (± 0.9) years old. 13 Methods: The study group consisted of 40 volunteers (men and women) aged 14-17 (juniors 14 and younger juniors) who have been practicing medium distance running for at least two years. 15 The study followed a randomised, double-blind, placebo-controlled design. All subjects 16 attended a familiarisation session on day 0 before the test commenced. The subjects were 17 randomly divided into two groups: supplements group and placebo group. A similar training 18 cycle protocol was used in both groups. Daily sRPE values, countermovement jump 19 measurement as well as blood creatine kinase and lactate dehydrogenase were measured during 20 12-day training period. 21 Results: After the end of the training cycle, a significant (p = 0.002) decrease in the 22 countermovement jump (CMJ) height was found in the placebo group when compared to the 23 baseline measurement. In the supplements group, there was no decrease in the 24 countermovement jump value, which was close to the baseline level after the end of the training 25 cycle (p>0.05). During the 12-day training period, statistically significant changes in creatine 26 kinase and lactate dehydrogenase levels were recorded between the supplements and placebo 27 groups; its concentration increased during the training weeks similarly, and decreased on rest. 28 All the changes were at a comparable level in both groups. The research results indicate that 29 the supplement combination used in the supplements group prevented a reduction in the CMJ 30 values. In contrast to supplements group, in the placebo group, the CMJ changes were 31 statistically significant: a noticeable (p = 0.002) decrease in CMJ was noted between the 32 baseline measurement and the 6th measurement. The well-being of the subjects from both groups changed significantly during the training period, and the intergroup differences in the mood level were similar and not statistically significant. 35 Conclusions: The results of this study indicate that the daily co-supplementation with 36 β-hydroxy-β-methylbutyrate (6 g) and L-arginine α-ketoglutarate (8 g) during the 12-day 37 intensive training camp may prevent deterioration of lower limb muscle power measured by the 38 CMJ test in the well-trained youth track and field athletes. lactate dehydrogenase.

peak power, average power, maximum speed, and post-exercise lactate concentration was 84 recorded during the Wingate test on a cycle ergometer. Moreover, taking into consideration the 85 initial values, the supplementation of HMB increased the peak power output, average power, 86 maximum speed and post-exercise lactate concentrations, with a simultaneous reduction of the 87 time needed to achieve peak power, compared to the placebo group. 88 There is also some evidence that ARG supplementation could have a beneficial influence 89 on anaerobic capacity. Yavuz et al. (9) examined the significance of a single dose of L-arginine 90 (1.5 g ·10 kg -1 body weight) given to 9 male national and international level wrestlers after a 91 12-hour (night) fast. The athletes performed an incremental bicycle ergometer test to exhaustion 92 during which several parameters (oxygen consumption, heart rate and plasma lactate levels) 93 were measured. The results showed that the significant difference was observed in time to 94 exhaustion which was prolonged in the L-arginine group (1386.8±69.8 s) when compared to 95 placebo (1313±90.8 s) (p<0.05). 96 Bailey et al. (10) studied the effects of a 3-day supplementation with 6 g/d of L-arginine 97 (dissolved in 500 ml of water) which was taken by 9 trained, healthy active men 60 min before 98 exercise on a cycle ergometer. The participants were requested to complete 6-minute cycling 99 bouts with a moderate intensity; the last cycle was continued until failure, and it was used as a 100 measure of exercise tolerance. There was significant increase in plasma nitrite and time to task 101 failure in the ARG group when compared to the placebo group. In both groups, there was also 102 significantly lower oxygen consumption (VO2) during moderate-intensity cycle exercise; the 103 VO2 slow component amplitude was reduced during severe-intensity exercise, favouring the 104 ARG group. 105 Campbell et al. (11) reported significant increases in the 1-RM strength and anaerobic 106 power (Wingate test) among 35 resistance-trained healthy males after supplementation of 12 g of AAKG (6 g of L-arginine) per day for eight weeks. The authors observed a significant 108 increase in the peak power in the AAKG group in comparison to the placebo group. 109 Mor et al. (12) observed no statistically significant difference before and after 110 supplementation between the experimental (6 g of ARG) and the placebo (6 g of wheat bran) 111 groups consisting of 28 active male football players who played in amateur leagues during the 112 14-day research. Nevertheless, the post supplementation recovery lactic acid levels showed a 113 more rapid reduction in the experimental group when compared to the placebo one. A similar 114 relationship was observed for the indicator of muscle injury expressed by a decreased level of 115 LDH enzymes in the ARG group. All this suggests that the supplementation with L-arginine 116 helps not only to excrete lactic acid from the body more effectively but also increases muscle 117 recovery by lowering the level of LDH enzymes when compared to the placebo group.

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The use of L-arginine in post-workout recovery was also raised in the research of 119 McConell et al. (13), who submitted 9 endurance-trained males to a steady-state cycle 120 ergometer exercise for 120 minutes. During the last 60 minutes of cycling, the subjects were 121 given either a placebo or L-arginine HCl (30 g at 0.5 g/min) intravenously. ARG infusion 122 significantly increased skeletal muscle glucose clearance when compared to placebo, without 123 increasing plasma insulin concentration. The authors suggested that L-arginine increased NO 124 production, which then elevated muscle glucose uptake and might helped muscle recovery.

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Most ARG studies indicate that this amino acid has no or little effect on anaerobic capacity.

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However, some experiments show directional activity in this area, mainly due to the presence 127 of NO (nitric oxide) deriving from ARG, which appears to be useful for protecting muscle from 128 being injured and aids their recovery. Similar, though much better described results are 129 associated with HMB and the enhancement of the sarcolemma integrity properties via higher 130 availability of cytosolic cholesterol (14), inhibiting protein degradation (15), decreasing cell 131 apoptosis (16), increasing protein synthesis (mTOR pathway; 14,15), stimulating the growth hormone (GH)-insulin-like growth factor-1 (IGF-1) axis and enhancing muscle stem cells 133 proliferation and differentiation (16). 134 It would be interesting to know whether these two popular dietary supplements used 135 simultaneously would show an additive effect, especially noticeable during intense anaerobic 136 workouts. Meanwhile, it should be emphasised that this combination of supplements has not 137 been previously studied.

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Therefore, the purpose of this study was to check whether two popular supplements,  also required to refrain from taking any nutritional supplements or ergogenic aids for the two 154 weeks preceding the study. They were also asked to not to take any additional supplements 155 during the duration of the study. The volunteers gave their written consent to participate in the 156 study.
The study followed a randomised, double-blind, placebo-controlled design. All subjects 158 attended a familiarisation session on day 0 before the test commenced. The subjects were also 159 requested not to eat or drink for 2 hours before each training session. During the familiarization 160 session, the participants were shown and explained the rules for completing a well-being 161 questionnaire and a session RPE (sRPE) protocol; they were also informed about planned tests 162 during the entire12-day experiment ( Table 1) as well as their order on day 1 (  Table 2. Daily regimen of meals, supplementation and frequency of training as well as samples 178 and data collection during the 12-day study period.

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The training units were identically arranged for both groups and had the same volume.

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Each day, the selected training unit (morning or afternoon) was carried out with a greater load.  Fatigue and well-being assessment 227 The day before the camp began, as well as every morning during its duration, a 228 psychometric survey was carried out before the start (17). The survey comprised of five    immediately before blood samples were to be taken.

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The first blood samples were taken in the morning on the first training day (baseline). The 271 results from 6 measurement points were collected.

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No subjects reported any adverse events or side effects following the ingestion of the 283 supplement or placebo. The level of sRPE at the individual measuring points during the training 284 period in both groups was similar (Fig. 1); it proved that the athletes from both experimental 285 groups had comparable training load during their workout. During the 12-day training period, 286 statistically significant changes in creatine kinase were noted; however, the changes in both 287 groups were at a similar level (Fig. 2). Identical changes were also observed for LDH -the statistically significant (Fig. 3).

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The changes in CMJ performance in the analysed period were particularly interesting.

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In the supplements group, no significant differences (p>0.05) were noted between the 295 individual CMJ measurements. In contrast, in the placebo group, the CMJ changes were 296 statistically significant: a noticeable (p = 0.002) decrease in CMJ was noted between the 297 baseline measurement and the 6th measurement. At the same time, a considerable increase in 298 CMJ (p = 0.02) between the 6th and the 7th measurement was also recorded. Finally, when the 299 training period was completed (the last measurement), a significant (p = 0.002) decrease in the 300 CMJ height was observed in the placebo group compared to the baseline measurement. There 301 were no such changes registered in the SUP group; the post-workout CMJ performance was 302 close (p>0.05) to baseline (Fig. 4). The well-being of the subjects from both groups changed 303 significantly during the training period, and the intergroup mood differences were similar 304 (Fig. 5).

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The purpose of this study was to check whether the intensive use of two popular 311 supplements, β-hydroxy-β-methylbutyrate (HMB) and L-arginine α-ketoglutarate (AAKG), group. It should be emphasised that it was only after the camp ended that power 332 supercompensation was to be expected. It can be then concluded that the supplementation 333 allows us to stabilise the power level and carry out the planned training, without the need to correct training loads. Research to date (22,23,24) indicates that during the training period, 335 the CMJ height may either decrease or not undergo significant changes. The authors suggest 336 that this may be a result of fatigue accumulation. The co-supplementation of HMB and AAKG 337 could prevent fatigue accumulation and maintain lower limb strength.

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The chemical form of L-arginine used in the study, L-arginine α-ketoglutarate, as well   (27). This effect can also be caused by a decrease in the 356 concentration of lactate and ammonia in the bloodstream (28) or an increase in the glucose 357 absorption efficiency by muscle cells (13) to which ARG also contributes.  In this study, AAKG and Ca-HMB were co-administered in the SUP group. 6.5 g 381 derived from 10 g AAKG (8 capsules) was the set optimal daily dose of L-arginine. The dosage 382 of 6 g increased muscular blood flow which was correlated with nitric oxide production (31). empty stomach may increase the concentration of this amino acid in the blood by more than 386 330% within 1 hour. It is recommended in the literature to take products based on arginine and 387 its forms within approx. 60 minutes before planned exercise, especially since the half-life tested 388 at the optimal dose is about 80 minutes (32).

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Based on the scientific data, it has been observed that the effect of HMB is dose-390 dependent (33; 34, 35). In scientific research, the most commonly used doses of HMB include 391 1.5 g/d, 3 g/d or exceptionally 6 g/d (36). It is assumed that the optimal model for minimising 392 the damage to the trained muscle is a supplementation protocol of 1 g of Ca-HMB taken three 393 times a day with meals. For athletes who want to reduce the length of post-exercise recovery, 394 it is recommended to consume 3 g Ca-HMB 60 min before exercise (33,35).

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A study was carried out to check the effect of HMB supplementation on the level of 396 muscle tissue damage markers after endurance exercise (20 km cross-country run). The 397 participants were randomly assigned to a placebo group or a group supplemented with 3 g HMB 398 per day for six weeks. After the end of the supplementation period, a 20 km run test was carried 399 out, which showed statistically significant lower levels of both CK and LDH activity in the 400 athletes regularly taking HMB. At the same time, in both groups, the peak CK level was 401 recorded 24 hours after the 20 km run. (37). No similar results were obtained in our study. In 402 the cited example, the supplementation period was three times longer.

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The study protocol was based partly on the literature data. It was decided to use 6 g 404 HMB to check if this dosage is sufficient to positively influence the analysed parameters in the 405 limited period of the 12-day training camp. The fact that the plasma HMB half-life is 2.5h when 406 administered as calcium salt (Ca-HMB) and that taking 3 g of Ca-HMB would result in the 407 peak concentration of pure HMB in the bloodstream after 1 hour (38) contributed to Ca-HMB and AAKG being co-administered three times a day about 60 minutes before the physical 409 activity. The use of higher doses than those most commonly found in the literature was aimed 410 at optimising the rate at which the expected effects would appear (reduced level of the muscle 411 cell damage markers, counteracted decrease in lower limb power, improved well-being and 412 lower subjective feeling of effort intensity (sRPE)). Statistically significant differences were 413 observed only for the countermovement jump.

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The limitations of the study 416 In our opinion, it is also necessary to assess the effects of co-supplementation with HMB and 417 AAKG after the end of the camp (training period), when after a period of complete rest, muscle 418 power can significantly increase (supercompensation). Perhaps then other supplementation 419 effects could also be observed. The results of this study indicate that the daily co-supplementation with AAKG (8 g) and Ca-423 HMB (6 g) during the 12-day intensive training camp may prevent deterioration of lower limb