{"id":{"repo_id":"exeter","oai_identifier":"oai:figshare.com:article/32130499"},"canonical_url":"https://search.dev.ndltd.org/etd/exeter/oai:figshare.com:article/32130499","repository":{"repo_id":"exeter","name":"University of Exeter","base_url":"https://api.figshare.com/v2/oai"},"display":{"title":"The effect of whey protein-polyphenol on the recovery of muscle function and strength following eccentric exercise- the myogenic and neural contributions to eccentric exercise.","abstract":"Maximal eccentric contractions result in noteworthy declines in force-generating capacity due to the high intramuscular forces generated in lengthened muscle, especially in individuals unaccustomed to such exercise. Despite the typical characteristics of exercise-induced muscle damage (EIMD), the complete mechanistic underpinning of EIMD remains to be fully determined, particularly with respect to the neuromuscular junction's influence on recovery during an acute 3-hour period and more prolonged 24-hour and 48-hour periods. Nutritional strategies to promote recovery after eccentric exercise have been studied with whey protein and polyphenols, both of which support recovery via muscle protein synthesis and antioxidant & anti-inflammatory effects, respectively. However, whether their combined effect supports recovery above that of supplementing independently remains to be directly determined. Firstly, during the COVID lockdown and restrictions on human research, we surveyed 190 recreationally active females and males and found that the recreationally active population consumes protein supplements primarily in line with the expected benefits of muscle growth and recovery (1-6), however, the lack of structured exercise among this surveyed population may limit the ability to achieve these expected benefits. A novel finding and an important future consideration for researchers is the lack of knowledge among recreationally active individuals about the benefits derived from non-animal compared to animal protein sources, with inconsistent findings on whether plant-based proteins can be sufficient to support muscle recovery. As trends towards more sustainable protein sources grow, the lack of clear knowledge highlights the need to conduct research and share findings effectively to maximise understanding and application in the general population. The role of the neuromuscular junction in the EIMD-induced decline in force generating capacity was investigated in recreationally active females (n = 7) and males (n = 16) (Chapter 4). Maximum isometric force production declined by 66.3 ± 13.3 %con, and recovery was accelerated with protein-pomegranate supplementation. Plasma agrin concentration, a proxy measure of NMJ function and integral to NMJ stability and integrity, in part via acetylcholine receptor clustering, also declined at 24h but did not differ between groups. In the subsequent study (Chapter 5), conducted in 19 recreationally active individuals (n = 11 females), the anabolic response to whey protein-cherry supplementation was compared to that of an isocaloric carbohydrate placebo beverage (PLA), alongside an assessment of acute (first 3h recovery) changes in key proteins (agrin and C-terminal agrin fragments (CAF)) associated with NMJ function. PRO-POL, compared to PLA, resulted in an increase in plasma amino acid (total, essential, and branched-chain) concentration. However, myofibrillar protein synthesis rate (MyoFSR) did not increase after the eccentric exercise or consumption of PRO-POL. Nor did PRO-POL consumption attenuate the ~13% decline in muscle function at 3h compared to PLA. Plasma agrin concentration decreased comparably between PLA and PLA-PRO from baseline (-5.7 ± 9.7 �se) at 1h (-12.1 ± 14.9 �se) and 2h (-10.5 ± 12.3 �se) in response to eccentric exercise, with no change in CAF. Muscle gene expression responses corroborate this finding, with some differences between conditions in the expression of genes associated with the agrin-LRP4-MuSK signalling pathway and muscle mass regulation (i.e. mTOR), with limited expression of muscle injury-associated genes. Finally, we investigated whether a combined protein-polyphenol supplement enhanced recovery from resistance-type exercise to a greater extent than protein alone. The assessment of mRNA gene expression and myofibrillar protein synthesis provided novel insights into the molecular mechanisms underlying early remodelling and the pathways that drive muscle anabolism and neuromuscular junction function. Due to limitations in the study design and the nutritional supplement analysis, it was not possible to confidently test this hypothesis, and this question remains unresolved. In this thesis, we have shown that recovery of knee extensor force-generating capacity after eccentric exercise is assisted by consumption of a whey protein pomegranate beverage. In contrast, consumption of a whey protein-cherry supplement did not increase myofibrillar protein synthesis over 3h, 24h or 48h and did not improve recovery from EIMD. A primary and novel finding of this thesis is associated with the exploration of the NMJ response and contribution following eccentric exercise, in which a decline in plasma agrin was evident as early as 3h with mild EIMD (~20%) and at 24h with more notable EIMD (~60%). This change in agrin was not observed in conjunction with any change in CAF. The proposed dysfunction in NMJ function, indicated by a decline in agrin concentration, was corroborated by a change in muscle gene expression of signalling pathways associated with NMJ function. Finally, due to uncontrollable circumstances, it was not possible to confirm that the combination of protein and polyphenol results in improved recovery compared with protein alone, and this remains a valuable question to be examined.<p></p>","abstract_html":"Maximal eccentric contractions result in noteworthy declines in force-generating capacity due to the high intramuscular forces generated in lengthened muscle, especially in individuals unaccustomed to such exercise. Despite the typical characteristics of exercise-induced muscle damage (EIMD), the complete mechanistic underpinning of EIMD remains to be fully determined, particularly with respect to the neuromuscular junction&#x27;s influence on recovery during an acute 3-hour period and more prolonged 24-hour and 48-hour periods. Nutritional strategies to promote recovery after eccentric exercise have been studied with whey protein and polyphenols, both of which support recovery via muscle protein synthesis and antioxidant &amp; anti-inflammatory effects, respectively. However, whether their combined effect supports recovery above that of supplementing independently remains to be directly determined. Firstly, during the COVID lockdown and restrictions on human research, we surveyed 190 recreationally active females and males and found that the recreationally active population consumes protein supplements primarily in line with the expected benefits of muscle growth and recovery (1-6), however, the lack of structured exercise among this surveyed population may limit the ability to achieve these expected benefits. A novel finding and an important future consideration for researchers is the lack of knowledge among recreationally active individuals about the benefits derived from non-animal compared to animal protein sources, with inconsistent findings on whether plant-based proteins can be sufficient to support muscle recovery. As trends towards more sustainable protein sources grow, the lack of clear knowledge highlights the need to conduct research and share findings effectively to maximise understanding and application in the general population. The role of the neuromuscular junction in the EIMD-induced decline in force generating capacity was investigated in recreationally active females (n = 7) and males (n = 16) (Chapter 4). Maximum isometric force production declined by 66.3 ± 13.3 %con, and recovery was accelerated with protein-pomegranate supplementation. Plasma agrin concentration, a proxy measure of NMJ function and integral to NMJ stability and integrity, in part via acetylcholine receptor clustering, also declined at 24h but did not differ between groups. In the subsequent study (Chapter 5), conducted in 19 recreationally active individuals (n = 11 females), the anabolic response to whey protein-cherry supplementation was compared to that of an isocaloric carbohydrate placebo beverage (PLA), alongside an assessment of acute (first 3h recovery) changes in key proteins (agrin and C-terminal agrin fragments (CAF)) associated with NMJ function. PRO-POL, compared to PLA, resulted in an increase in plasma amino acid (total, essential, and branched-chain) concentration. However, myofibrillar protein synthesis rate (MyoFSR) did not increase after the eccentric exercise or consumption of PRO-POL. Nor did PRO-POL consumption attenuate the ~13% decline in muscle function at 3h compared to PLA. Plasma agrin concentration decreased comparably between PLA and PLA-PRO from baseline (-5.7 ± 9.7 �se) at 1h (-12.1 ± 14.9 �se) and 2h (-10.5 ± 12.3 �se) in response to eccentric exercise, with no change in CAF. Muscle gene expression responses corroborate this finding, with some differences between conditions in the expression of genes associated with the agrin-LRP4-MuSK signalling pathway and muscle mass regulation (i.e. mTOR), with limited expression of muscle injury-associated genes. Finally, we investigated whether a combined protein-polyphenol supplement enhanced recovery from resistance-type exercise to a greater extent than protein alone. The assessment of mRNA gene expression and myofibrillar protein synthesis provided novel insights into the molecular mechanisms underlying early remodelling and the pathways that drive muscle anabolism and neuromuscular junction function. Due to limitations in the study design and the nutritional supplement analysis, it was not possible to confidently test this hypothesis, and this question remains unresolved. In this thesis, we have shown that recovery of knee extensor force-generating capacity after eccentric exercise is assisted by consumption of a whey protein pomegranate beverage. In contrast, consumption of a whey protein-cherry supplement did not increase myofibrillar protein synthesis over 3h, 24h or 48h and did not improve recovery from EIMD. A primary and novel finding of this thesis is associated with the exploration of the NMJ response and contribution following eccentric exercise, in which a decline in plasma agrin was evident as early as 3h with mild EIMD (~20%) and at 24h with more notable EIMD (~60%). This change in agrin was not observed in conjunction with any change in CAF. The proposed dysfunction in NMJ function, indicated by a decline in agrin concentration, was corroborated by a change in muscle gene expression of signalling pathways associated with NMJ function. Finally, due to uncontrollable circumstances, it was not possible to confirm that the combination of protein and polyphenol results in improved recovery compared with protein alone, and this remains a valuable question to be examined.&lt;p&gt;&lt;/p&gt;","abstract_has_math":false,"creators":["Amy Booth (21038759)"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-04-23T00:00:00Z","date_published":"2026-04-23T00:00:00Z","updated_at":"2026-07-27T19:33:10Z","subjects":["Neuromuscular Junction","Eccentric Exercise","Whey Protein","Polyphenol","Recovery"],"languages":[],"rights":["All rights reserved","Open Access after 2028-11-12"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["10779/exe.32130499.v1"],"render_values":[{"text":"10779/exe.32130499.v1","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Amy Booth (21038759)"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2026-04-23T00:00:00Z"]},{"key":"dc:relation","label":"Dc Relation","values":["https://figshare.com/articles/thesis/The_effect_of_whey_protein-polyphenol_on_the_recovery_of_muscle_function_and_strength_following_eccentric_exercise-_the_myogenic_and_neural_contributions_to_eccentric_exercise_/32130499"]},{"key":"dc:type","label":"Dc Type","values":["Text","Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Neuromuscular Junction","Eccentric Exercise","Whey Protein","Polyphenol","Recovery"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["All rights reserved","Open Access after 2028-11-12"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10779/exe.32130499.v1"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Maximal eccentric contractions result in noteworthy declines in force-generating capacity due to the high intramuscular forces generated in lengthened muscle, especially in individuals unaccustomed to such exercise. Despite the typical characteristics of exercise-induced muscle damage (EIMD), the complete mechanistic underpinning of EIMD remains to be fully determined, particularly with respect to the neuromuscular junction's influence on recovery during an acute 3-hour period and more prolonged 24-hour and 48-hour periods. Nutritional strategies to promote recovery after eccentric exercise have been studied with whey protein and polyphenols, both of which support recovery via muscle protein synthesis and antioxidant & anti-inflammatory effects, respectively. However, whether their combined effect supports recovery above that of supplementing independently remains to be directly determined. Firstly, during the COVID lockdown and restrictions on human research, we surveyed 190 recreationally active females and males and found that the recreationally active population consumes protein supplements primarily in line with the expected benefits of muscle growth and recovery (1-6), however, the lack of structured exercise among this surveyed population may limit the ability to achieve these expected benefits. A novel finding and an important future consideration for researchers is the lack of knowledge among recreationally active individuals about the benefits derived from non-animal compared to animal protein sources, with inconsistent findings on whether plant-based proteins can be sufficient to support muscle recovery. As trends towards more sustainable protein sources grow, the lack of clear knowledge highlights the need to conduct research and share findings effectively to maximise understanding and application in the general population. The role of the neuromuscular junction in the EIMD-induced decline in force generating capacity was investigated in recreationally active females (n = 7) and males (n = 16) (Chapter 4). Maximum isometric force production declined by 66.3 ± 13.3 %con, and recovery was accelerated with protein-pomegranate supplementation. Plasma agrin concentration, a proxy measure of NMJ function and integral to NMJ stability and integrity, in part via acetylcholine receptor clustering, also declined at 24h but did not differ between groups. In the subsequent study (Chapter 5), conducted in 19 recreationally active individuals (n = 11 females), the anabolic response to whey protein-cherry supplementation was compared to that of an isocaloric carbohydrate placebo beverage (PLA), alongside an assessment of acute (first 3h recovery) changes in key proteins (agrin and C-terminal agrin fragments (CAF)) associated with NMJ function. PRO-POL, compared to PLA, resulted in an increase in plasma amino acid (total, essential, and branched-chain) concentration. However, myofibrillar protein synthesis rate (MyoFSR) did not increase after the eccentric exercise or consumption of PRO-POL. Nor did PRO-POL consumption attenuate the ~13% decline in muscle function at 3h compared to PLA. Plasma agrin concentration decreased comparably between PLA and PLA-PRO from baseline (-5.7 ± 9.7 �se) at 1h (-12.1 ± 14.9 �se) and 2h (-10.5 ± 12.3 �se) in response to eccentric exercise, with no change in CAF. Muscle gene expression responses corroborate this finding, with some differences between conditions in the expression of genes associated with the agrin-LRP4-MuSK signalling pathway and muscle mass regulation (i.e. mTOR), with limited expression of muscle injury-associated genes. Finally, we investigated whether a combined protein-polyphenol supplement enhanced recovery from resistance-type exercise to a greater extent than protein alone. The assessment of mRNA gene expression and myofibrillar protein synthesis provided novel insights into the molecular mechanisms underlying early remodelling and the pathways that drive muscle anabolism and neuromuscular junction function. Due to limitations in the study design and the nutritional supplement analysis, it was not possible to confidently test this hypothesis, and this question remains unresolved. In this thesis, we have shown that recovery of knee extensor force-generating capacity after eccentric exercise is assisted by consumption of a whey protein pomegranate beverage. In contrast, consumption of a whey protein-cherry supplement did not increase myofibrillar protein synthesis over 3h, 24h or 48h and did not improve recovery from EIMD. A primary and novel finding of this thesis is associated with the exploration of the NMJ response and contribution following eccentric exercise, in which a decline in plasma agrin was evident as early as 3h with mild EIMD (~20%) and at 24h with more notable EIMD (~60%). This change in agrin was not observed in conjunction with any change in CAF. The proposed dysfunction in NMJ function, indicated by a decline in agrin concentration, was corroborated by a change in muscle gene expression of signalling pathways associated with NMJ function. Finally, due to uncontrollable circumstances, it was not possible to confirm that the combination of protein and polyphenol results in improved recovery compared with protein alone, and this remains a valuable question to be examined.<p></p>"]},{"key":"dc:title","label":"Title","values":["The effect of whey protein-polyphenol on the recovery of muscle function and strength following eccentric exercise- the myogenic and neural contributions to eccentric exercise."]}]}],"canonical_facts":{"dc:creator":["Amy Booth (21038759)"],"dc:date":["2026-04-23T00:00:00Z"],"dc:description":["Maximal eccentric contractions result in noteworthy declines in force-generating capacity due to the high intramuscular forces generated in lengthened muscle, especially in individuals unaccustomed to such exercise. Despite the typical characteristics of exercise-induced muscle damage (EIMD), the complete mechanistic underpinning of EIMD remains to be fully determined, particularly with respect to the neuromuscular junction's influence on recovery during an acute 3-hour period and more prolonged 24-hour and 48-hour periods. Nutritional strategies to promote recovery after eccentric exercise have been studied with whey protein and polyphenols, both of which support recovery via muscle protein synthesis and antioxidant & anti-inflammatory effects, respectively. However, whether their combined effect supports recovery above that of supplementing independently remains to be directly determined. Firstly, during the COVID lockdown and restrictions on human research, we surveyed 190 recreationally active females and males and found that the recreationally active population consumes protein supplements primarily in line with the expected benefits of muscle growth and recovery (1-6), however, the lack of structured exercise among this surveyed population may limit the ability to achieve these expected benefits. A novel finding and an important future consideration for researchers is the lack of knowledge among recreationally active individuals about the benefits derived from non-animal compared to animal protein sources, with inconsistent findings on whether plant-based proteins can be sufficient to support muscle recovery. As trends towards more sustainable protein sources grow, the lack of clear knowledge highlights the need to conduct research and share findings effectively to maximise understanding and application in the general population. The role of the neuromuscular junction in the EIMD-induced decline in force generating capacity was investigated in recreationally active females (n = 7) and males (n = 16) (Chapter 4). Maximum isometric force production declined by 66.3 ± 13.3 %con, and recovery was accelerated with protein-pomegranate supplementation. Plasma agrin concentration, a proxy measure of NMJ function and integral to NMJ stability and integrity, in part via acetylcholine receptor clustering, also declined at 24h but did not differ between groups. In the subsequent study (Chapter 5), conducted in 19 recreationally active individuals (n = 11 females), the anabolic response to whey protein-cherry supplementation was compared to that of an isocaloric carbohydrate placebo beverage (PLA), alongside an assessment of acute (first 3h recovery) changes in key proteins (agrin and C-terminal agrin fragments (CAF)) associated with NMJ function. PRO-POL, compared to PLA, resulted in an increase in plasma amino acid (total, essential, and branched-chain) concentration. However, myofibrillar protein synthesis rate (MyoFSR) did not increase after the eccentric exercise or consumption of PRO-POL. Nor did PRO-POL consumption attenuate the ~13% decline in muscle function at 3h compared to PLA. Plasma agrin concentration decreased comparably between PLA and PLA-PRO from baseline (-5.7 ± 9.7 �se) at 1h (-12.1 ± 14.9 �se) and 2h (-10.5 ± 12.3 �se) in response to eccentric exercise, with no change in CAF. Muscle gene expression responses corroborate this finding, with some differences between conditions in the expression of genes associated with the agrin-LRP4-MuSK signalling pathway and muscle mass regulation (i.e. mTOR), with limited expression of muscle injury-associated genes. Finally, we investigated whether a combined protein-polyphenol supplement enhanced recovery from resistance-type exercise to a greater extent than protein alone. The assessment of mRNA gene expression and myofibrillar protein synthesis provided novel insights into the molecular mechanisms underlying early remodelling and the pathways that drive muscle anabolism and neuromuscular junction function. Due to limitations in the study design and the nutritional supplement analysis, it was not possible to confidently test this hypothesis, and this question remains unresolved. In this thesis, we have shown that recovery of knee extensor force-generating capacity after eccentric exercise is assisted by consumption of a whey protein pomegranate beverage. In contrast, consumption of a whey protein-cherry supplement did not increase myofibrillar protein synthesis over 3h, 24h or 48h and did not improve recovery from EIMD. A primary and novel finding of this thesis is associated with the exploration of the NMJ response and contribution following eccentric exercise, in which a decline in plasma agrin was evident as early as 3h with mild EIMD (~20%) and at 24h with more notable EIMD (~60%). This change in agrin was not observed in conjunction with any change in CAF. The proposed dysfunction in NMJ function, indicated by a decline in agrin concentration, was corroborated by a change in muscle gene expression of signalling pathways associated with NMJ function. Finally, due to uncontrollable circumstances, it was not possible to confirm that the combination of protein and polyphenol results in improved recovery compared with protein alone, and this remains a valuable question to be examined.<p></p>"],"dc:identifier":["10779/exe.32130499.v1"],"dc:relation":["https://figshare.com/articles/thesis/The_effect_of_whey_protein-polyphenol_on_the_recovery_of_muscle_function_and_strength_following_eccentric_exercise-_the_myogenic_and_neural_contributions_to_eccentric_exercise_/32130499"],"dc:rights":["All rights reserved","Open Access after 2028-11-12"],"dc:subject":["Neuromuscular Junction","Eccentric Exercise","Whey Protein","Polyphenol","Recovery"],"dc:title":["The effect of whey protein-polyphenol on the recovery of muscle function and strength following eccentric exercise- the myogenic and neural contributions to eccentric exercise."],"dc:type":["Text","Thesis"]},"updated_at":"2026-07-27T19:33:10Z"}