The Efficacy of Sap Obtained from Commiphora gileadensis Against Cadmium-Induced Liver Toxicity in Rats: Crimson Publishers

The Efficacy of Sap Obtained from Commiphora gileadensis Against Cadmium-Induced Liver Toxicity in Rats by Amal S Soliman in Research in Medical & Engineering Sciences: Peer Reviewed Research in Medical & Engineering Sciences

Abstract

Cadmium (Cd), a toxic heavy metal, ranks among the top ten environmental threats to human health, adversely affecting vital organs such as the kidneys, liver, pancreas, lungs, and testes. This study investigates the protective effects of Commiphora gileadensis (CG) sap against Cd-induced liver damage in male rats. Forty-two healthy adult male albino rats were randomly divided into seven groups: G1 (control), G2 (50mg/L cadmium chloride in drinking water), G3 and G4 (100mg/kg and 400mg/kg CG sap, respectively), G5 (50mg/L cadmium chloride + 100mg/kg CG sap), G6 (50mg/L cadmium chloride + 400mg/kg CG sap), and G7 (1% Tween 80, 1mL/rat as a vehicle). Cadmium exposure significantly reduced the antioxidant capacity and impaired liver functions. However, co-administration of CG sap markedly ameliorated these adverse effects, improving antioxidant capacity and restoring hepatic function. These findings suggest that CG sap has potential as a natural therapeutic agent to mitigate cadmium toxicity and its associated environmental hazards.

Keywords:Commiphora gileadensis; Cadmium; Liver functions; Oxidative stress; Antioxidants

Introduction

The livers are critical organs responsible for xenobiotic metabolism and storage, making them highly susceptible to damage from toxic substances. Cadmium (Cd), a non-essential transition metal, is a significant environmental contaminant known for its toxicity to humans and animals. Cd exposure occurs through industrial and agricultural activities, as well as contaminated food, water, and cigarette smoke [1,2]. Due to its long biological half-life (25-30 years), Cd bioaccumulates in tissues, primarily in the liver, causing severe oxidative stress and tissue damage [3].

Cd toxicity is associated with various health complications, including hepatic syndrome, characterized by impaired liver functions and increased morbidity and mortality. The toxic effects of Cd are largely mediated by its induction of reactive oxygen species (ROS), leading to oxidative stress, mitochondrial dysfunction, and damage to cellular components [4,5]. Antioxidants, both synthetic and natural, have been investigated for their ability to counteract Cd-induced oxidative damage. Among natural antioxidants, plant-derived compounds such as phenolics and flavonoids have shown significant protective effects [6].

Commiphora gileadensis (CG), commonly known as Balessan, is a medicinal plant native to arid regions, including Saudi Arabia. Traditionally, CG sap has been used for its anti-inflammatory, antimicrobial, and wound-healing properties [7,8]. Recent studies have highlighted the antioxidant potential of CG sap, which may offer protective effects against heavy metal toxicity [9,10]. This study evaluates the ameliorative effects of CG sap on Cd-induced liver damage in albino rats, with a focus on histopathological changes and biochemical markers.

Materials and Methods

Plant material

Commiphora gileadensis sap was collected by damaging the bark of the plant in the Medina region of Saudi Arabia.

In Vitro antioxidant activity assessment

One g of plant sap was extracted with 10 mL of ethanol using a magnetic stirrer at 1,000rpm (IKA, Staufen, Germany).

Total Phenolic Content (TPC)

TPC was estimated using the Folin-Ciocalteu method [11] with gallic acid as the standard.

Cupric Reducing Antioxidant Capacity (CUPRAC)

The CUPRAC assay was performed as reported by [12], using Trolox as the standard antioxidant. The experiment was conducted in triplicates, with values expressed as Trolox equivalents per gram of dry weight.

Total Flavonoid Content (TFC)

TFC was determined using the aluminum chloride colorimetric method [13]. Absorbance was measured at 405nm, with results expressed as quercetin equivalents (QE).

Ferric Reducing/Antioxidant Power (FRAP)

The FRAP assay was conducted following the method of [14], using Trolox as the standard.

DPPH radical-scavenging activity

The DPPH assay was carried out using the method of [15], with results measured at 517nm.

ABTS radical-scavenging activity

The ABTS assay was performed as described by [16], with results expressed at 734nm.

Median Lethal Dose (LD50)

The LD50 of CG sap was determined using 12 male Swiss albino mice (20-25g). The mice were divided into four groups (n=3 per group) and acclimated for seven days. Doses of 1.0, 2.5, and 5.0g/ kg body weight of CG sap in 1% Tween 80 were administered orally. Observations for mortality and behavioral changes were conducted for 48 hours [17].

Animal Experimentation

Forty-two adult male albino rats (200-220g) were obtained from the Faculty of Pharmacy, King Saud University, Riyadh, Saudi Arabia. After a two-week acclimation period, the rats were randomly divided into seven groups (n=6 per group) as follows: Control Group (G1; NC): Normal drinking water and standard diet. Positive Control (G2: Cd): 50mg/L cadmium chloride in drinking water. Experimental Groups (G3: CG1, G4: CG4): 100mg/kg and 400mg/kg CG sap orally. Combination Groups (G5, G6): 50mg/L cadmium chloride + 100mg/kg or 400mg/kg CG sap orally. Vehicle Control (G7): 1mL of 1% Tween 80 orally.

All treatments were administered daily for 60 days. Cadmium chloride was supplied via drinking water, while CG sap and vehicle were administered orally by gavage [18].

Blood sampling and histopathological examination

At the end of the experimental period, blood samples were collected under light ether anesthesia for serum preparation to measure biochemical parameters using commercial kits. Liver tissues were harvested, preserved in 10% buffered formalin, and processed for histopathological analysis.

Statistical analysis

Results were reported as mean ± SEM (Standard Error of Mean). To assess the influence of the seven treatment groups on the different biochemical parameters, one- way analysis of variance (ANOVA) by Tukey multiple tests as post hoc test were used. The value of P<0.05 was used to indicate statistical significance. ALL Analyses were done using Statistical Package (IBM SPSS Statistics, version 26).

Result

The median lethal dose (LD50) of C. gileadensis sap

The findings indicated that none of the tested doses of Commiphora gileadensis, even at levels as high as 5000mg per kilogram of body weight, resulted in no fatalities within the various groups (Table 1).

Table 1:The number of Mortality of different groups of mice with different administered doses.

In vitro assessment of antioxidant activity

C. gileadensis had strong scavenging values depend on our result (Figure 1). The results showed that DPPH value of CG to be 75.27%, the ABTS value of CG was 98%, the TPC value of CG to be 101.47mg GAE/g and the TFC value of CG to be 77.13mg QE/g and the values of FRAP and CUPRAC were 40.72 and 36.93 respectively.

Figure 1:In vitro assessment of antioxidant activity {total phenolic content (TPC), cupric reducing antioxidant capacity (CUPRAC), total flavonoid content (TFC), ferric reducing/antioxidant power (FRAP), 2,2-diphenyl-1- picrylhydrazyl radical scavenging activity (DPPH), 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation assay (ABTS).

Effect of CG sap, and cadmium chloride on serum antioxidant concentration

Table 2:Effect of CG sap, and cadmium chloride on antioxidant concentration of CAT, MDA and total antioxidant.

NC (normal control): Cd (cadmium): CG1 (Commiphora gileadensis 100mg/kg b. wt.): CG4 (Commiphora gileadensis 400mg/kg b. wt.): Values within the same column carrying different letters are significantly different at P<0.05 based on Tukey post hoc multiple comparison test. Values are expressed as mean ± S.E. (N=6 rats).

Data observed that administration of C. gileadensis sap non significantly affected the serum level of catalase, total antioxidants and malondialdehyde (MDA) compared with the values of control groups (Table 2). The present data showed a significant (P<0.05) decreased in the serum level of catalase enzyme and total antioxidants in cadmium chloride treated group compared to all other groups of the study. While co- administration of C. gileadensis sap plus cadmium chloride significantly enhanced the values of serum levels of catalase enzyme; and total antioxidants and these values did not differ significantly with those of control groups. Administration of cadmium chloride significantly increased the serum level of MDA compared to other groups of the experiment. However, co-administration of C. gileadensis sap significantly decreased the MDA level but remained higher significantly than control values (Table 2).

Biochemical analysis

Biochemical analysis of various damage and function markers were analyzed. These markers include liver damage and function markers such as alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), total protein (TP) and albumin (ALB). These tests aids determination of which part of the liver is damaged, and depending on the pattern of elevation, can assist organizing a differential diagnosis. Besides these markers, the kidney function markers such as the urea, creatinine and uric acid levels in the blood serum were investigated.

The liver function markers were analyzed including ALT, AST and ALP as shown in Table 3. As can be observed from Table, A significant increase in AST (305.11±15.03), ALP (261.16±8.35), and ALT (144.83±7.79) levels in the blood serum is clear in CD cohort which indicates the induction of liver injury. This reduction was alsoobserved even when the C. gileadensis dose to 100 and 400mg. The effect and reduction of liver function marker upon exposure to CD- C. gileadensis contributes to the potential protective effect of C. gileadensis against liver injury.

Table 3:The effect of different treatments on the serum levels of ALP, ALT and AST of rats intoxicated with CD for 8 weeks (values are expressed as mean ± SE.

NC (normal control): Cd (cadmium): CG1 (Commiphora gileadensis 100mg/kg b. wt.): CG4 (Commiphora gileadensis 400mg/kg b. wt.): Values within the same column carrying different letters are significantly different at P<0.05 based on Tukey post hoc multiple comparison test. Values are expressed as mean ± S.E. (N=6 rats).

Histopathological examination of liver in the different groups

Control group: No histopathological changes were detected in the examined livers of these rats. Figure 2A revealed normal histological criteria.

Cadmium chloride group: The livers of the treated rats showed congestion and dilatation of central and portal veins (Figure 2B). focal aggregates of lymphocytes and macrophages, surrounded by coagulative necrosis of hepatocytes characterized by loss of cellular detail, individualized shrunken hepatocytes with hyper eosinophilic cytoplasm and pyknotic nuclei (Figure 2C).

Figure 2:A. Liver of control rat showing normal histological appearance of central vein (CV) and hepatocytes (H). H&E stainx200. B. Liver of rat administered 50mg cadmium chloride showing congestion and dilatation of portal vein (PV). H&E stainx200. C. Liver of rat administered 50mg cadmium chloride showing focal aggregates (asterisk) of lymphocytes and macrophages, surrounded by coagulative necrosis of hepatocytes characterized by loss of cellular detail, individualized shrunken hepatocytes with hyper eosinophilic cytoplasm and pyknotic nuclei (arrow). H&E stainx200.

C. gileadensis sap 100mg/ kg b. wt. group: The liver showed normal histological appearance like control group. Occasionally, the liver showed mild congestion of central veins (Figure 3A).

C. gileadensis sap 400mg/ kg b. wt. group: The liver showed normal histological appearance like control group. Occasionally, the liver showed congestion of portal veins and mild lymphocytic infiltrate in portal areas (Figure 3B).

C. gileadensis sap 400mg/ kg b. wt. plus cadmium chloride group: The livers showed mild congestion of central veins with normal histological appearance of hepatocytes and portal areas (Figure 3C).

Figure 3:A. Liver of rat administered 100mg plant sap/kg b. wt. showing mild congestion of central veins (CV) and normal histological appearance of hepatocytes. H&E stain x 200. B. Liver of rat administered 400mg plant sap/kg b. wt. showing congestion of portal vein (PV) and mild lymphocytic (arrow) infiltrate in portal areas. H&E stain x 200. C. Liver of rat administered 400mg plant sap/kg b. wt. and 50mg cadmium chloride showing mild congestion of central veins (CV) with normal histological appearance of hepatocytes (H) and portal areas (PA). H&E stain x 200. D. Liver of rat administered 400mg plant sap/kg b. wt. and 50mg cadmium chloride showing mild biliary hyperplasia and small numbers of lymphocytes (arrowhead) and macrophages in portal areas. H&E stain x 400.

Discussion

This study is the first to explore the protective effects of Commiphora gileadensis (CG) sap against cadmium (Cd)- induced toxicity in liver tissues. Plants have large number of bioactive compounds with high antioxidant activity. Studies for the determination of the antioxidant activity of different plant species could contribute to revealing the value of these species as a source of new antioxidant compounds. Plants live in habitats with extreme environmental conditions (high temperatures, water stress, and high light irradiation in summer), for which they have developed different adaptive mechanisms, both morphological and physiological. One of these mechanisms is the prevention of oxidative stress, keeping ROS under dangerous levels [19], and using them for efficient signaling [20]. Secondary metabolites of plants, specifically phenols, can adjust the concentration of ROS, thus activating a network of biochemical events to increase tolerance, hence the importance of studying the antioxidant activity of typical plant species as C. gileadensis. The protective effects against oxidative stress are attributed to the natural antioxidants found in herbs and spices. These aromatic ingredients harbor compounds such as polyphenols, flavonoids, and phenolic compounds, which act as scavengers of free radicals, however antioxidants are substances that can scavenge free radicals and prevent the oxidative damage they generate in cells. In the present study, C. gileadensis sap had strong antioxidant activity by studying its DPPH, ABTS, FRAP and CUPRAC values. Some authors, confirmed the previous findings on some parts of CG other than its sap as leaves and bark. [21], reported the DPPH value of CG to be 75.27% which is lower than the value reported in this research. However, [22] reported higher values than in the present study. While, the ABTS value of CG to be 98% which is higher than the value reported in this research. [21] reported the TPC value of CG to be 101.47 mg GAE/g and the value was lower than the value reported in this research. [23] reported the TFC value of CG to be 77.13mg QE/g which is lower than the value reported in this research. However, there is no report in the literature of the values of FRAP and CUPRAC. The differences between results may be due to different parts used, extraction conditions such as methodology and solvents used in the extraction. The differences in results also, may be due to geographical locations of samples.

C. gileadensis sap is of wide safety margin as confirmed in the present study as LD50 was above 5g /kg b. wt. These results align with previous research conducted by [24] who reported that C. gileadensis sap safe up to 5g/kg b. wt. Consequently, any substance that demonstrates no harmful effects at a dosage of 5000mg/ kg is categorized as being ‘practically non-toxic.’ Based on these outcomes, it can be concluded that Commiphora gileadensis sap is regarded as safe and practically non- toxic [25]. Cadmium is one of the most toxic heavy metals and affects both animals and humans via induction of cellular oxidative stress and subsequent elevation of free radicals. Strong evidence suggests the harmful effect of cadmium. The livers are the organs with the highest concentration of cadmium present, after absorption [26]. When cadmium enters the body, it is transported into the bloodstream via erythrocytes and albumin and is then accumulated in liver and gut [27]. Cadmium excretion from the body is slow and occurs via the kidneys, urine, saliva, and milk during lactation. Cd exposure can result in a variety of adverse effects, such as renal and hepatic dysfunction, pulmonary edema, testicular damage, osteo-malacia, and damage to the adrenals and hemopoietic system [28]. It has been proved that after exposure, Cd enters the blood and binds to the erythrocyte membranes and blood albumin and then is transported to liver, where it bounds to metallothionein (MT) [28]. The Cd-MT complex is then released back into circulation [29]. and accumulates in the blood system, kidney, liver, lung, testis, brain, and bone [30].

In the current study, liver injury was evident in the Cd group, manifested by decreased total protein levels, increased liver enzymes, AST, ALT and ALP. These results are in agreement with earlier studies [31,32]. Recent reports have suggested that lysosome instability caused by Cd toxicity resulted in the leakage of hepatic enzymes, including ALT, ALP and AST, into the bloodstream [32]. CG sap is rich source of polyphenols. Polyphenols have been reported to possess a membrane stabilizing activity by inhibiting the generation of ROS induced by Cd and maintain the cell membrane structural integrity [33]. Our findings exhibited elevation in liver enzymes in Cd-treated group. These findings come in the same line with [34], who revealed that; Cd toxicity causing hepatic cell damage and its enzymes AST, ALP and ALT released into circulation, therefore the level of these enzymes in blood elevated than normal. Histological examination of liver tissue showed liver injury in the Cd-treated group, where hepatocytes lost their characteristic regular arrangement. Most hepatocytes exhibited vacuolation, and their nuclei were partially pyknotic. In contrast, CG a co- treatment showed hepatic-protective effects, proven by restoration of liver structure and function in these groups. The hepatic-protective effects of CG sap observed in this study, supporting the opinion that CG restored liver architecture and function following cadmium toxicity.

These histological abnormalities were found to be reduced in CG + Cd groups. The co- treatments with CG led to almost complete restoration of the Cd induced renal damage and restored the standard values of the kidney function markers.

Cd-induced hepatic dysfunction in this study was most likely due to an imbalance of oxidant/antioxidant capacity in the tissues. The present study showed a significant increase in MDA levels and a decrease in the activity of antioxidant enzymes, such as serum total antioxidants and CAT. The endogenous antioxidants are important scavengers of free radicals, which eventually lead to cellular dysfunction and death [6]. Our findings agreed with previous reports demonstrating that cadmium induces kidney toxicity by enhancing ROS formation and GSH consumption and inhibiting an antioxidant-mediated defense system [33]. Additionally, the nephroprotective effect of CG was owned to the improvement of renal oxidation and decrease of serum creatinine urea levels which are in consistence with [35]. In the present study, CG sap contains a high content of flavonoids. [36] studied one of the main actions of flavonoids, which enhanced renal function and diminished apoptotic and oxidative stress markers. Thus, the properties of CG may cause some of the Cd to be retained, preventing further adverse effects usually induced by toxic metals. In the current study, the observed Cd- induced hepatic histopathological abnormalities are consistent with previous results depicting similar alterations in rats treated with Cd administered as CdCl2. Most importantly, our study has shown that CG pretreatment possesses potent hepatic protective and antioxidative properties against cadmium toxicity.

Conclusion

Collectively, administration of cadmium chloride induces adverse effects on the liver functions and decreases the antioxidative status. Co-administration of CG sap with cadmium significantly mitigated the previous hazard effects by ameliorating the antioxidant status. The plant sap showed no signs of toxicity were observed during the acute toxicity study and the LD50 value indicates that sap is to be safe. Phytochemical investigation is also proposed to isolate the active fraction and eventually the pure compound.

Acknowledgement

The Researchers would like to thank the Deanship of Graduate Studies and Scientific Research at Qassim University for financial support (QU-APC-2024-9/1).

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Visual-cognitive Skills and Physical Qualities in Elite Soccer: Practical Considerations for Training and Return-to-Play Protocols: Crimson Publishers

Visual-cognitive Skills and Physical Qualities in Elite Soccer: Practical Considerations for Training and Return-to-Play Protocols by Lukasz Bortnik in Research & Investigations in Sports Medicine: Peer Reviewed Research & Investigations in Sports Medicine

 

Abstract

Elite soccer is increasingly demanding, requiring players to cover greater distances at higher speeds while making rapid decisions under high-pressure scenarios. These demands place significant strain on neurophysiological capacities, highlighting the need for integrated training that combines physical, technical-tactical and visual-cognitive development. This is particularly critical for athletes returning from long-term injury, who require both physical rehabilitation and neurocognitive re-adaptation to safely resume competition. Traditional Return-to-Play protocols often overlook compensatory central nervous system adaptations, increasing the risk of movement errors. Contemporary approaches emphasise visual-cognitive skills, supported by divided attention (managing multiple tasks) and selective attention (prioritizing relevant stimuli), while Blood Flow Restriction (BFR) training provides a promising adjunct during rehabilitation, especially when combined with Virtual-Reality (VR) techniques. Integrating these cognitive and physical strategies may enhance performance, reduce movement errors and facilitate safer re-integration into elite soccer.

Keywords: Blood flow restriction; Virtual-cognitive skills; Soccer RTP

Introduction

Elite soccer continues to evolve, with rising physical and technical-tactical demands across many European competitions. As the intensity of the modern game increases, players are expected to cover greater running distances at higher speeds and perform in more dynamic, high-pressure scenarios where decisions made in fractions of a second can determine match outcomes [1]. These evolving demands suggest that players’ neurophysiological capacities are being tested to new limits [2,3]. In practical settings, this underscores the critical need to develop physical and technical-tactical abilities in tandem with visual-cognitive skills. This is especially pertinent for players returning from long-term injury, who must undergo physical rehabilitation and a period of re-adaptation before safely rejoining team training and competitive play [4]. These individuals face an elevated risk of movement errors, often due to compromised motor control under the complex and unpredictable demands of elite competition [4]. For example, evidence indicates that altered brain and spinal cord function (negative neuroplasticity) may persist for years after knee surgery, even following a return to full activity [5]. In addition, persistent biomechanical deficits have been observed long after knee reconstruction, particularly during the penultimate foot contact of the injured limb in change-of-direction tasks [6]. These findings suggest that RTP protocols should place greater emphasis on movement mechanics and sensorimotor control, alongside traditional performance outcomes. Ultimately, a paradigm shift is needed in rehabilitation. The one that integrates elements of “brain training” and cognitive training to more comprehensively address the long-term consequences of injury.

Modern training and preparation must therefore utilize a deep analytical approach and explicitly integrate key visual-cognitive aspects into these processes. Skills such as perception, anticipation and rapid reaction should be considered essential components of contemporary training programs [7]. Both divided and selective attention are vital to stimulate visual-cognitive processes effectively. Divided attention (dual-tasking) refers to the ability to manage multiple tasks simultaneously or switch between them without attentional loss [8]. Selective attention (Table 1) involves identifying relevant and ignoring irrelevant stimuli [9].

Table 1:Definitions, divisions and examples of selective attention in football.

Visual-Cognitive Processes: Practical Applications

Practitioners might ask how visual-cognitive aspects could be applied in practical settings. In real-match scenarios, the concepts of anticipation and reaction can be utilized in various ways to enhance player performance and impose professional development. Table 2 & 3 depict real-world situations that offensive and defensive positions could experience during official matches. In practical settings, embedding visual-cognitive processes in individual and team-based training, including rehabilitation and Return-to-Play (RTP) protocols, is essential for a holistic and safe transition back to full match performance. When injuries limit movement and on-pitch sessions are not possible however, alternative approaches must be considered. A notable example is an Anterior Cruciate Ligament (ACL) injury. It is worth noting that rupture and reconstructive surgery lead to a disruption of sensory input from the knee to the Central Nervous System (CNS), resulting in altered motor behaviours [10]. Consequently, ACL injury should be regarded as a multifaceted musculoskeletal condition, as it encompasses not only mechanical and movement impairments but also cognitive and neurological disruptions. Failing to address these dimensions within rehabilitation, prevention and risk assessment strategies may result in incomplete management and a higher likelihood of recurrent problems [11]. In such cases, a long recovery and multi-staged rehabilitation are required, gradually transitioning from gym-based to pitch-based specific exercises [12] (Figure 1). Rehabilitation, even at early stages, should include tasks that challenge attention, working memory, and visual-spatial processing as shown in Figure 2 & 3. Training plans at more advanced stages must consider the individual’s characteristics and positional demands, where soccer players anticipate, decide and quickly react to constantly changing environments that mimic game-like scenarios [12-15]. For instance, developing the ability to press aggressively, win the ball high and transition instantly into attack has been considered a decisive factor in modern soccer [13]. Figure 1 presents a drill designed to connect defensive pressing behaviors with a quick counter-attack, emphasizing perception, anticipation and reaction in high-tempo game situations. The main aim during this exercise is to condition players for repeated high-intensity efforts in realistic scenarios while enhancing individual and collective awareness in attack and defense [14]. Another practical and progressive approach is the Visual-Cognitive Control-Chaos Continuum (VC-CCC) proposed by Taberner and colleagues [15]. This framework outlines how RTP strategies can progressively integrate various physical and cognitive objectives, which is shown in Table 4. By adopting such structured, cognitively integrated training frameworks, practitioners can maximize the RTP protocols and better prepare athletes for complex, fast-paced scenarios of modern soccer and ultimately enhance their readiness for the match demands.

Table 2:Examples of anticipation scenarios for offensive players in football match-play.

Table 3:Examples of reaction scenarios for defensive players in football match-play.

Figure 1:Specific offensive-defensive drill (3v1 high pressure and counter-attack): a) 3D drill set up; b) 3v1 possession where player nr 6 (blue) applies high pressure to win the ball; c) once possession has been re-gained, counter-attack is initiated; d) 3 blue players counter-attack and 1 red defends (3v1); e) 2 red players are making recovery runs to support defense (3v3); f) blue players quickly enter the box to finish an attack, which must be performed as quickly as possible to use numerical advantage in its early phase. Perform 2 sets of 6-8 actions lasting 20-30 seconds. Use 1:2-3 work-to-rest-ratio. Group activity: 9-15 players. Perception/Anticipation/Reaction. Adopted from Bortnik L [14].

Figure 2:VR goggles used during an ACL rehabilitation.

Figure 3:Virtual reality applications used to improve cognitive skills: A) Inhibition & eye-hand coordination; B) Scanning ability & reaction.

Table 4:Examples of integrated objectives during the Visual-Cognitive Control-Chaos Continuum (VC-CCC).

Blood Flow Restriction and Ischemic Preconditioning

Blood Flow Restriction (BFR), first developed in the 1990s, involves the application of external pressure to partially restrict blood flow during low-load exercise [16]. A growing body of evidence indicates that BFR training promotes muscle hypertrophy, strength, peak power, aerobic capacity, recovery and proprioception [17-21]. In addition to physical outcomes, BFR has been associated with enhanced cognitive performance, such as improved cognitive function in elderly populations [22] and increased cognitive flexibility in young athletes [23]. BFR shorts in particular have been shown to be feasible, practical and safe in applied environments [24] (Figure 4a). Importantly, low-load exercise with BFR elicits adaptations comparable to those achieved with high-intensity training [25]. This makes BFR especially relevant in contexts where high mechanical loads are undesirable, such as Anterior Cruciate Ligament (ACL) rehabilitation or in the days immediately before and after competition in soccer [26]. The primary physiological mechanisms underlying BFR include tissue ischemia, which induces metabolic stress, cellular swelling, anabolic hormone upregulation, and increased expression of neurotrophins such as Brain-Derived Neurotrophic Factor (BDNF) [27]. Together, these mechanisms support both physical and cognitive adaptations while reducing joint stress.

Ischemic Preconditioning (IPC) is a BFR method that involves periods of circulatory ischemia, usually 3 to 4 x 5 minutes, followed by circles of reperfusion of similar or shorter duration in the limbs [28]. This approach elicits high hypoxic stress inducing vasodilation, improving muscle blood flow, enhancing oxygen delivery and ultimately positively affecting various exercise performance [29]. Preconditioning efficacy has been widely reported on strength, power and endurance capabilities [30,31]. From a research perspective however, interests should be directed more towards the IPC effect on sensory-motor patterns and muscular coordination in various athletic populations including soccer players. Evidence suggests that IPC might enhance sensory and proprioceptive feedback during physical activity to correct movements and augment its quality. That might ultimately improve physical performance and reduce potential injury risk, which would be considered of high importance in an athletic population [20,21,26].

Virtual Reality: A Novel Technique in Practical Settings

Virtual Reality (VR) provides a computer-generated threedimensional environment accessed through head-mounted displays and motion controllers, creating an immersive sense of presence in virtual space [32]. VR has been applied in both clinical and sporting contexts to enhance motor and sensory function, cognitive processes and perceptual skills, all of which play a critical role in decision-making in team sports [33]. Research has demonstrated that movement patterns and motor control are largely comparable between physical environments and virtual conditions [34]. Furthermore, VR has proven effective in the evaluation and rehabilitation of gait [35], highlighting its potential as both an assessment and training tool. This technique is particularly valuable when physical loading must be limited, for example during injury rehabilitation or recovery phases in a weekly microcycle in soccer [26]. Although BFR and VR have each demonstrated significant promise, no studies to date have examined their combined use in sport [36]. Conceptually, their integration could provide synergistic benefits, enhancing proprioception, motor and cognitive skills, postural control and physiological adaptations such as muscle size, strength and endurance (Figure 4b). A potential protocol (Figure 5) could involve applying BFR at ~70% limb occlusion pressure (LOP; <200mmHg) bilaterally, as recommended by Neal BS et al. [24], for 3 sets of 5 minutes during VR training, interspersed with 2-minute reperfusion periods [21]. This combined approach may augment both sensorimotor and cognitive outcomes while supporting neuromuscular adaptation. Future research should examine this novel paradigm with particular attention to its relevance for soccer performance, rehabilitation and recovery [37].

Figure 4:New training and RTP methods including: A) Blood Flow Restriction (BFR); B) Combined VR and BFR.

Figure 5:Practical protocol combining blood flow restriction and virtual reality training during rehabilitation and RTP.

Summary and Conclusion

Elite soccer is becoming increasingly demanding, requiring players to produce higher physical outputs while simultaneously making rapid decisions under complex, high-pressure scenarios. These evolving demands place significant strain on neurophysiological capacities, highlighting the need for integrated training approaches that develop physical and technical-tactical skills and visual-cognitive abilities. Such an approach is particularly important for athletes returning from long-term injuries, such as ACL ruptures, where Return-to-Play (RTP) protocols must address both physical rehabilitation and neurocognitive re-adaptation to ensure safe and effective reintegration into competition. Failure to address these cognitive and perceptual components may increase the risk of movement errors and compromise performance.

Emerging technologies provide promising tools to support cognitive development in soccer players. Virtual Reality (VR) offers a low-cost, low-impact method to enhance perception, reaction speed, inhibitory control, eye-hand coordination, scanning ability and visual processing efficiency. VR is particularly advantageous for injured athletes, allowing them to maintain cognitive engagement while minimizing physical stress, thereby facilitating smoother transitions from controlled training environments to on-pitch performance. Additionally, VR-based applications can complement conventional gym- and field-based training routines, providing a powerful adjunct for players at all ages and competitive levels. Furthermore, the integration of VR with Blood Flow Restriction (BFR) training may amplify cognitive and neurophysiological adaptations by combining perceptual-cognitive engagement with physiological stimulation. This synergistic approach may represent potentially a promising tool for rehabilitation and performance enhancement, particularly during periods when high-intensity physical training is not feasible. Systematic research is warranted to explore the efficacy, optimal protocols and long-term benefits of this combined methodology.

From a practical approach, coaches and performance staff could incorporate technology-enhanced cognitive drills alongside traditional physical conditioning, ensuring training scenarios replicate the attacking and defending demands of competition. Exercises should challenge decision-making, attention and perception under realistic constraints, while progression should be tailored to each player’s injury status and readiness. Integrating VR and BFR into structured RTP programs may accelerate cognitivemotor re-integration, enhance tactical awareness and reduce the likelihood of re-injury, ultimately supporting safer and more effective preparation for elite match play.

Key Takeaways

A. Cognitive skills training should focus on perception, anticipation, decision-making and rapid reaction.
B. Divided and selective attention should be trained in practical settings.
C. Virtual Reality (VR) provides low-cost, low-impact cognitive training.
D. VR enhances cognitive skills and could facilitate smoother transition from controlled environments to on-pitch performance.
E. BFR can be combined with VR to potentially enhance neurophysiological and cognitive adaptations in addition to well-established physiological benefits.
F. Athletes could perform VR-based training while applying BFR at ~70% of limb occlusion pressure (<200mmHg), structured as 3 × 5-minute bouts with 2-minute reperfusion periods.
G. BFR can be useful when high-intensity physical training is not feasible (e.g., during injury rehabilitation or when fatigued).

Practical Implications

a) Design drills that replicate attacking and defending scenarios relevant to player positions.
b) Progress training based on injury status, readiness and competitive demands.
c) Integrate VR + BFR to potentially accelerate cognitivemotor re-integration and reduce re-injury risk.

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