Tennis Home-Training during First Italy Lockdown COVID-19: A Pilot Study in Young Athletes during Lockdown

COVID-19 pandemic has imposed an Italy national lockdown between 9 March and 3 May 2020, limiting the ability of individuals to exercise/training outdoors. The aim of this study was based on the construction of remote-personalized-training protocols in tennis and examined the effects of a home-based intervention. Sixteen young athletes, divided into four groups in accord with the level of play and the pre-existing technical-tactical preparation, were trained by tennis-coach using simple equipment (i.e., balance board, medicine ball, steps). Physiological parameters (HR, SaO 2 ), the ability to execute technical gestures in conditions of stress/fatigue, development of adaptation and motor reaction skills, as well as eye-manual coordination; execution of movements at high speeds and precision, prevention of muscle and joint injuries, were monitoring. A questionnaire able to evaluate the subjective perception was administered. Athletes have demonstrated, by means of this latter, the beneficial effects of home-training during the lockdown. Concluding, the remote home-training, offered to athletes one option to maintain “normal” training practices, in view of a return to the tennis court. Furthermore, at today, in post-pandemic environments and behaviors, the results suggest that remote home-training intervention may help foster meaningful improvements in young athletes, strengthening intrinsic/subjective motivation.


Introduction
In 2020, the World Health Organization (WHO) declared the Public Health Emergency of International Concern in January and Pandemic of coronavirus disease  in March. Since then, world people's lives changed radically. At the end of July 2021, the global situation counted 195,886,929 confirmed cases and 4,189,148 deaths, while in Italy there were, at the same date, 4,330,739 confirmed cases and 128,010 deaths (World Health Organization, WHO) [1]. COVID-19 had impact of on the life aspects of all people in every part of the world [2,3,4,5]. From, March 9 to May 3, 2020, the government of Italy imposed a national lockdown, restricting the movement of the population, except for necessity, work, and health circumstances. The "lockdown" measures, despite being widely approved by public opinion, were also described as the largest suppression of constitutional rights in the history of the republic (Costituzione Italiana) [6].
The lockdown restrictions have negative socio-psychological impacts both on mental and physical health (i.e., isolation, depression, anxiety, insomnia) and, as reported by Hawkley and Capitanio [7], long-term isolation creates stress, negative emotion, impaired cognition. Furthermore, Rodrí guez-Rey et al. [8] in their study have reported that adverse psychological effects have occurred on Spanish people, and young people and women suffered more than the others. Moreover, during the COVID-19 lockdown, in southern Italy, a cross-sectional study confirms a negative impact on young and adults [9]. It has also been reported that physical inactivity during the COVID-19 pandemic lockdown was deleterious for the cardiovascular system [10], has increased sedentary behaviors [11], with poorer dietary choices and increased alcohol consumption [12,13].
The pandemic of coronavirus disease (COVID-19) leads to all Worldwide movement restrictions that have caused significant disruption to athlete's training and consequently sporting competitions [14,15,16].
Many athletes were not able to perform sport-specific training, due to movement restrictions [17], especially in children, adolescents, and young adults [18]. Many athletes have trained at home, often without specialist equipment or supervision [13,19].
In contrast, other athletes opportunistically used the 'lockdown' time during the pandemic in a positive way, to 'upskill' perhaps in preparation for their lives after sport [20,21]. Despite emerging evidence, demonstrating beneficial effects of home-training, the overall effectiveness of home-training for maintaining optimal levels of sport-specific conditioning remains unclear [22].
It is well known that sports practice has beneficial effects not only on the physical body but also on mental care [23,24]. According to Garber et al. [25] and based on the recommendation of the American College of Sports Medicine, exercise improves physical and mental health and/or fitness in most persons without taking account of their training habits. It has also been reported that home-based tactics could include aerobic activities, balance and flexibility exercises, muscular strength and endurance training [26].
Recently, Loh et al. [27] have reported a positive effect of a home-based exercise program on social and emotional well-being among older patients with cancer and likewise, positive effects in people with chronic heart failure after individualized home-based physical program [28]. Moreover, it has been demonstrated that physical activity has beneficial effects in neurodegenerative diseases [29] and in older individuals to improve muscle mass and function [30,31].
Tennis is one of the most popular sports in the world, with 1.12% of the world's population (about 75 million) participating in tennis. Tennis is played at every level and at any age from 4 to over 80 years old. It is therefore considered a valuable sport for maintaining healthy physical activity levels in middle aged and older adults [32].
Tennis is a highly specific sport that requires specific spaces [33] and beneficial effects on the musculoskeletal function of tennis players respected to non-players are reported. It is a static and dynamic sport and it has many health benefits: it increases brain power, improves handeye coordination, reduces stress, decreases cardiovascular disease, increases fitness levels, leads to stronger bones and muscles [34]. Tennis playing requires cognitive control, visuo-spatial orientation and specific tennis motor skills for efficient decisions [35]. Furthermore, tennis players with enhanced decision-making skills can use movement-pattern information to determine shot selection, reduce their response delay times and, hence, improve their stroke performance [36].
The idea of this study was based on the construction of personalized training protocols, elaborated and differentiated according to different parameters, such as the level of play of the participants, the availability of space in one's home, the availability of equipment and tools suitable for training suited to their characteristics, as well as the technical-metabolic needs required for maintaining good physical-technical -tactics, with a view to a future return to activities on the court. Each student was allowed to train directly with tennis coaches, remotely, each in their own homes, adapting protocols to the technical material and environments available to the various athletes. Then, the aim of this study was to find a solution to fight this constant and forced motor decline in daily life, during the COVID-19 lockdown in 2020.

Subjects
This study was carried out during the Italian lockdown and it involved 16 volunteers' young athletes, mean age 18.5±2.1 years (14 males: 18.4±2.2 years 2 females: 19 years) of a tennis club (Modena, Italy). Anthropometric measures: height, weight, and BMI were assessed and are reported in Table 1.
The athletes have been divided in four groups, according to the level of play and the pre-existing technical-tactical preparation. Different activities were carried out to satisfy the physical-technical-tactical demands of all those involved, adapting the workouts to their needs and characteristic ( Table 2).  T1  T2  T3  T4  T1  T2  T3  T4  T1  T2  T3  T4   A   1      Briefly summarizing the temporal structure of the study, it is possible to say that the 4 groups, of 4 subjects each, had the opportunity to train, 2 times a week, for a total period of 9 weeks which covered approximately the entire duration of the national lockdown, from 2 March to 4 May 2020. The surveys were carried out at: 2 March (T1), 30 March (T2), 20 April (T3), 2 May (T4) 2020.
Tables 3, 4 and 5 describe the training program of the beginner group (A), the intermediate group (B) and the advanced groups (C and D). Each table describes the aims of the training for each week of the lockdown and the executive methods, the exercises, the duration and repetitions and the recovery time.
The training was obviously provided by a connection with "Video-Call" mode through the Zoom or Microsoft Teams platforms, with each group connected independently with the undersigned on their own dedicated weekly day.
The equipment included: Dunlop Fort All Court 3 & 4 tennis balls ("regular" type, used in tennis teaching from 14 years upwards); Balance Board (proprioception and balance training); Fitness elastic bands; Skipping Node; Medicine ball -3 or 5 kg; Mat; Chairs; Weights (dumbbells) varying from 1 to 5 kg; Steps or, as alternative, stairs.
The equipment used to monitor some parameters Remote training protocols have been customized according to the level of play and the technical-physical-tactical characteristics of each athlete. There are three fundamental points to which a tennis-coach must pay particular attention: I. Ability to execute technical gestures in conditions of stress and fatigue, as well as a strong development of adaptation and motor reaction skills, as well as eye-manual coordination;

II.
Execution of movements at high speeds that require maximum precision at the same time;

III.
Importance in the prevention of muscle and joint injuries.
The training evaluated parameters and the specific methodology are showed in Table 6 and 7.  Table 7. Specific methodology adopted for the athletes of the different groups.

Interval Training Time Round
Step up 10'' on 10'' off 10 rounds Lateral step up 10'' on 10'' off 10 rounds The structuring of the activities basically followed two steps of investigations and one of re-elaboration: A first phase of investigation in which proceeded to the detection (pre the lockdown due to COVID-19) of some parameters related to Heart Rate, using maximum shooting tests on the 300 meters, reproduced in the same way by all the participants in the project (i.e. environmental conditions, physical fatigue, rest). Information about the environments, tools and spaces already available within each their homes were asked.
In this second phase, following the investigations carried out on the family environments and on the physiological characteristics of each participating subject, coaches were able to start elaborating the different adapted activities and creating diversified groups.
A third phase of investigation in which it was administered a questionnaire (by phoning and video call) to each athlete who participated in. The questionnaire was structured as a Visual Analog Scale (VAS), able to evaluate the subjective perception. In fact, it has been reported that an ordinal scale based on subjective assessments, also used in the clinical and research fields, is a very commonly used tool for monitoring the subject's evolution in physical therapy. Moreover, it is applicable in many circumstances and it is a good method of assessing an athlete's response training [37]. The survey was tested with the following questions:

How do you rate this distance training experience?
The questionnaire was administered to athletes at T1, T2, T3 and T4.
The athletes with age of majority, involved in this study gave written informed consent, obtained through use of e-mail, in respecting the ethical principles of the Declaration of Helsinki, when minors athletes the signed written parental consents were obtained.

Statistical Analysis
All data were collected using an online questionnaire and video monitoring at different time points, where due tabulated in a excel spreadsheet (Microsoft, Washington, WA, USA) and analyzed using GraphPad Prism 9. 0. 2 (GraphPad So ware Inc., San Diego, CA, USA).
Considering the low number of athletes, we performed also the descriptive statistics. Percentage changes, defined as [(post-pre)/pre)*100], were used for the analysis to assess home-training effects.
Anthropometric and physiological parameters, were analyzed by non-parametric test, Friedman and post hoc Dunn's multiple comparison test was used to verify significant differences at the different time-points.
Significant level was set at p<0.05. Data are reported as [mean ± SD].

Results
During the two months, the young athletes added some mm to their height. Statistic tests show the significant difference in groups A and C (p<0.01 and p<0.02 respectively), but post hoc does not show the significant difference among time-point (Figure 1a). However, between T1 and T4 + 8mm of growth in both groups were reported.
Also, a significant increase was observed in change of weight in group C at T4 respect T1 (71.8±6.7 vs 69.8±6.8 kg, respectively, Figure 1b), while, not significant differences were observed in BMI (Figure 1c) among groups.
No significant differences in SaO 2 were recorded, where the mean value was 99.2±0.5%.  At the end of the remote-home-training, the feedback received from athletes, by VAS was positive, reaching all the objectives.
In details (Figure 2)

Discussion
It is widely known that physical activity and training have beneficial effects on physical, mental, and social health [18,19,23]; in particular, tennis and other rackets sports can be played by anyone at any level without distinction for age or sex [38]. The unexpected lockdown, due to the COVID-19 emergence, has destabilized all the population and especially the athletes, leading to decrease physical activity and the consequent well-being [39,40].
The current study reports the home-training perceptions of satisfaction of athletes during a "first lockdown in Italy in 2020".
The lockdown could have some negative effects on mental, emotional health, stress, and training motivation as reported [38,39,40,41,42] This because athletes experience an uncertainty about their return to competition and their performance level [43]. COVID-19 not only completely changed our lives but also took us by surprise. Having been taken by surprise, from one day to the next, we had to reinvent ourselves in order to survive, trying to continue the work that had been abruptly interrupted and trying to lighten the days of the young athletes. For this reason, with the means available and technology (i.e., smartphone, tablet,), we thought about this form of home-training.
It was not thought to be a success, as it turned out because the athletes may prefer the physical presence of their coach, as training at a medium-high level on your own isn't psychologically easy. Meeting the hands-on needs of instruction was be a challenge.
Not having any more available fields for carrying out training, the coach decided to elaborate and design training protocols as close as possible and corresponding to the technical-tactical-metabolic requirements of this sport, in order to make the experience as similar as possible to routine training, but obviously without using the ordinary surface and avoiding all direct interaction with other companions. We are aware that remote coaching had and has drawbacks and some limitations, but alas, it was and is the unique opportunity for both coaches and athletes during the COVID-19 pandemic, in particular during the first Italian lockdown in 2020.
The main question to solve was: how could it be possible to think of training perfectly respondent to the characteristics that a tennis lesson must have and, at the same time, be adapted to each subject involved according to his/her age, level of play, equipment and spaces available at home?
The answer certainly required an initial analysis of the characteristics of the athletes who participated in the project and, secondly, investigations into the familiar environments and the tools available. Therefore, this project firstly "studied" the participants by monitoring different metabolic and physical parameters, including BMI, Heart Rate max, Heart Rate at rest, reserve Heart Rate, and then subjected them to some questionnaires in order to have a sort of "inventory" ready of the material with which start work on.
The study of the technical-metabolic characteristics of the subjects participating in the project was certainly accompanied by a preliminary investigation on the actual availability of the same and precisely on the space-time availability (rooms in the house, tools, and free days), for which also the participants had to show their approval and their commitment to get involved. The experience to practice distance training for an indeterminate time was accepted by the subjects involved as a chance to continue training despite the forced lockdown.
Boys and girls have decided to rely on this project totally, without time limitations and with the pure desire to savor relative normality, which represents an outlet, of emotion and fun, that is sport.
Recent research in the field of sports medicine has also raised concerns about the impact of coronavirus disease on athletes' health. As reported in the literature [44,45] long-term detraining could bring a loss of endurance capacity and a loss of muscle strength and mass. These factors will significantly increase the risk of injury amongst athletes.
Lockdown period has presented absolutely unprecedented situation for all people and certainly a dramatic shift in teaching, and in the learning [46]. This was not the case only for the education (primary/higher) assessment practices, but also for all that is the recreational and sporting sphere.
The athletes involved in this study have demonstrated, by means of the questionnaire (VAS), the beneficial effects of home-training during the lockdown both on physical (e.g. HR measures might reflect (aerobic-based) adaptation and fatigue status, thence are able to represent the athlete's training status [47]) and mental well-being (Figure 3), even if, as we have been able to see from the answers, the greatest doubts remain on the technical and tactical preparation. However, our preliminary findings provide further insight compared to "outdoor" training methods.

Limitations
The authors are aware that the current study suffers from certain limitations as the sample size and the lack of any control group. However, we would like to emphasize that the coach-team consisted of 16 young athletes, and that everyone participated in the study. Athletes were divided into four groups according to the level of play and the pre-existing technical-tactical preparation, all have been included and analyzed in this pilot study. Given the scarcity of research including young athletes [48], and in particular tennis players, the sample size was been determined by accessibility. Because of the influence posed by this pandemic, it is important to use caution without generalizing when interpreting the data. As such, future researches in case of other blocking periods must extend the current findings.
Finally, we conclude that no measures were done when the athletes returned to the playing field after lockdown and that future studies may use a mixed approaches to confirm the current study's which was suggested in previous studies [19].

Conclusions
In conclusion, we can say that the remote home-training, offered athletes one option to maintain both "normal" training practices, in order to avoid a risk of detraining in athletes in view of a return to the tennis court.
Anyway, further studies, with the use of implemented platforms could be more appropriate and yield novel training programs in sports. To date, COVID-19 pandemic represents a global crisis that has forced athletes young/elite/not and coaches into an unknown situation.

Funding
This research received no external funding.

Institutional Review Board Statement
The study was conducted according to the guidelines of the Declaration of Helsinki.

Informed Consent Statement
Informed consent was obtained from all coaches involved in the study. Written informed consent has been obtained from the coaches to publish all data is available within the manuscript.

Data Availability Statement
All data is available within the manuscript.